Questions about the “Tatiya­vitthā­ra­sutta” SuttaCentral's
Pāli text of SN 48.17, “Tatiya­vitthā­ra­sutta” is,


  “Pañcimāni, bhikkhave, indriyāni. Katamāni pañca? Saddhindriyaṃ … pe … paññindriyaṃ—imāni kho, bhikkhave, pañcindriyāni. Imesaṃ kho, bhikkhave, pañcannaṃ indriyānaṃ samattā paripūrattā arahaṃ hoti, tato mudutarehi antarā­pari­nib­bāyī hoti, tato
  mudutarehi sasaṅ­khā­ra­pari­nib­bāyī hoti, tato mudutarehi uddhaṃsoto hoti akaniṭṭhagāmī, tato mudutarehi sakadāgāmī hoti, tato mudutarehi sotāpanno hoti, tato mudutarehi dhammānusārī hoti, tato mudutarehi saddhānusārī hoti. Iti kho, bhikkhave, paripūraṃ paripūrakārī ārādheti, padesaṃ padesakārī ārādheti. ‘Avañjhāni tvevāhaṃ, bhikkhave, pañcindriyānī’ti vadāmī”ti.


In this Sutta:


What are asaṅ­khā­ra­pari­nib­bāyī and sasaṅ­khā­ra­pari­nib­bāyī ?
What is the meaning of vadāmī?
Do dhammānusārī and saddhānusārī mean Cula Sotapanna?
Is the maximum of seven lives applicable to Cula Sotapanna?


Thanks.
What are asaṅ­khā­ra­pari­nib­bāyī and sasaṅ­khā­ra­pari­nib­bāyī ?


In SN 46.3, Bhikkhu Bodhi translates these terms as: 


'Nibbāna without exertion'
'Nibbāna with exertion'.


This translation appears inaccurate to me, since 'sankhara' here probably means 'thinking' rather than 'exertion' (although the practical meaning is the same). 

The terms 'asaṅ­khā­ra­pari­nib­bāyī' &amp; 'sasaṅ­khā­ra­pari­nib­bāyī' are described in AN 4.169, which states per the translation below:


  Cattāromecattārome?, bhikkhave, puggalā santo saṃvijjamānā lokasmiṃ.
  Katame cattāro?
  
  017.09. Bhikkhus, these four persons are evident in the world. What four?
  
  Idha, bhikkhave, ekacco puggalo diṭṭheva dhamme
  sasaṅ­khā­ra­pari­nib­bāyī hoti. Idha pana, bhikkhave, ekacco puggalo
  kāyassa bhedā sasaṅ­khā­ra­pari­nib­bāyī hoti. Idha pana, bhikkhave,
  ekacco puggalo diṭṭheva dhamme asaṅ­khā­ra­pari­nib­bāyī hoti. Idha
  pana, bhikkhave, ekacco puggalo kāyassa bhedā
  asaṅ­khā­ra­pari­nib­bāyī hoti.
  
  Here, bhikkhus, a certain person extinguishes here and now with
  substratum. A certain person extinguishes with substratum at death, a
  certain person extinguishes here and now without substratum. A certain
  person extinguishes without substratum at death,
  
  Bhikkhus, which person extinguishes here and now with substratum?
  
  Kathañca, bhikkhave, puggalo diṭṭheva dhamme
  sasaṅ­khā­ra­pari­nib­bāyī hoti? Idha, bhikkhave, bhikkhu
  asubhānupassī kāye viharati, āhāre paṭikūlasaññī, sabbaloke
  anabhi­rati­saññī, sabba­saṅ­khā­resu aniccānupassī. Maraṇasaññā kho
  panassa ajjhattaṃ sūpaṭṭhitā hoti. So imāni pañca sekhabalāni
  upanissāya viharati— saddhābalaṃ, hiribalaṃ, ottappabalaṃ,
  vīriyabalaṃ, paññābalaṃ. Tassimāni pañcindriyāni adhimattāni
  pātubhavanti—saddhindriyaṃ, vīriyindriyaṃ, satindriyaṃ,
  samādhindriyaṃ, paññindriyaṃ. So imesaṃ pañcannaṃ indriyānaṃ
  adhimattattā diṭṭheva dhamme sasaṅ­khā­ra­pari­nib­bāyī hoti. Evaṃ
  kho, bhikkhave, puggalo diṭṭheva dhamme sasaṅ­khā­ra­pari­nib­bāyī
  hoti.
  
  Here, bhikkhus, the bhikkhu abides reflecting loathsomeness in the
  body, loathsomeness in food, detachment from all the world, seeing
  impermanence in all determinations and the perception of death is
  thoroughly established in him. He abides relying on these five powers
  of a trainer- Such as the powers of faith, shame remorse, effort and
  wisdom. The five faculties of faith, effort, mindfulness,
  concentration and wisdom are sharp in him as a result he extinguishes
  here and now with substratum.
  
  Bhikkhus, which person extinguishes with substratum after death?
  
  Here, bhikkhus, the bhikkhu abides reflecting loathsomeness in the
  body, loathsomeness in food, detachment from all the world, seeing
  impermanence in all determinations and the perception of death is
  thoroughly established in him. He abides relying on these five powers
  of a trainer- Such as the powers of faith, shame remorse, effort and
  wisdom. The five faculties of faith, effort, mindfulness,
  concentration and wisdom are blunt in him as a result he extinguishes
  with substratum after death.
  
  Bhikkhus, which person extinguishes here and now without substratum?
  
  Here, bhikkhus, the bhikkhu secluded from sensual thoughts, angry
  thoughts, hurting thoughts and evil thoughts ... re ... and abides in
  the first higher state of mind. Overcoming thoughts and thought
  processes ... re ... abides in the second higher state of mind.
  Developing equanimity to joy and detachment ... re ... experiences
  pleasantness with the body too and abides in the third higher state of
  mind. To this the noble ones say abiding in pleasantness with
  equanimity. Dispelling pleasantness and unpleasantness and earlier
  having dispelled pleasure and displeasure, purifying mindfulness, so
  that unpleasantness or pleasantness does not enter the mind, he abides
  in the fourth higher state of mind. He abides relying on these five
  powers of a trainer- Such as the powers of faith, shame remorse,
  effort and wisdom. The five faculties of faith, effort, mindfulness,
  concentration and wisdom are sharp in him as a result he extinguishes
  without substratum here and now.
  
  Bhikkhus, which person extinguishes without substratum after death?
  
  Here, bhikkhus, the bhikkhu secluded from sensual thoughts, angry
  thoughts, hurting thoughts and evil thoughts ... re ... and abides in
  the first higher state of mind. Overcoming thoughts and thought
  processes ... re ... abides in the second higher state of mind.
  Developing equanimity to joy and detachment ... re ... experiences
  pleasantness with the body too and abides in the third higher state of
  mind. To this the noble ones say abiding in pleasantness with
  equanimity. Dispelling pleasantness and unpleasantness and earlier
  having dispelled pleasure and displeasure, purifying mindfulness, so
  that unpleasantness or pleasantness does not enter the mind, he abides
  in the fourth higher state of mind. He abides relying on these five
  powers of a trainer- Such as the powers of faith, shame remorse,
  effort and wisdom. The five faculties of faith, effort, mindfulness,
  concentration and wisdom are blunt in him as a result he extinguishes
  without substratum after death.
  
  Bhikkhus, these four persons are evident in the world.


The sutta is unambiguous. 'Asaṅ­khā­ra­pari­nib­bāyī' appears to mean 'extinguishing without using the sankhara aggregate', namely, the development of jhana, which is the stilling of thought. 'Sasaṅ­khā­ra­pari­nib­bāyī' appears to mean 'extinguishing with using the sankhara aggregate', namely, the development of wisdom or right view. 






  What is the meaning of vadāmī?


'Vadami' simply means 'speak' or 'I say' (it seems). 






  Do dhammānusārī and saddhānusārī mean Cula Sotapanna?


Dhamma-follower &amp; faith-follower appear to not be sotapanna (stream-enterer) but headed for sotappana (stream-entry). 


  Bhikkhus, the Dhamma well proclaimed by me thus is clear…free of patchwork. In the Dhamma well proclaimed by me thus, which is
  clear…free of patchwork, those bhikkhus who are Dhamma-followers or
  faith-followers are all headed for enlightenment. MN 22







  Is the maximum of seven lives applicable to Cula Sotapanna?


No. The suttas do not mention "seven more lives". The suttas only mention: "seven more", which obviously means "seven more fetters to breakthrough", as indicted by SN 13.1:


  In the same way, monks, for a disciple of the noble ones who is consummate in view, an individual who has broken through [to
  stream-entry], the suffering &amp; stress that is totally ended &amp;
  extinguished is far greater. That which remains in the state of having
  at most seven remaining [fetters] is next to nothing: it's not a
  hundredth, a thousandth, a one hundred-thousandth, when compared with
  the previous mass of suffering. That's how great the benefit is of
  breaking through to the Dhamma, monks. That's how great the benefit is
  of obtaining the Dhamma eye."