Sila before samatha, samatha before vipassana according to AN 11.1-3? In discourses given to monks in AN11.1, AN11.2 and AN11.3, the Buddha gave very similar messages on the purpose and benefit of virtue (sila) and how it leads to knowledge and vision of release.

I quote the Thanissaro translation of AN11.1:


  “Thus in this way, Ananda, skillful virtues (sīlā) have freedom from
  remorse as their purpose, freedom from remorse as their reward.
  Freedom from remorse (avippaṭisāro) has joy as its purpose, joy as its
  reward. Joy (pāmojjaṃ) has rapture as its purpose, rapture as its
  reward. Rapture (pīti) has serenity as its purpose, serenity as its
  reward. Serenity (passaddhi) has pleasure as its purpose, pleasure as
  its reward. Pleasure (sukhaṃ) has concentration as its purpose,
  concentration as its reward. Concentration (samādhi) has knowledge &amp;
  vision of things as they actually are as its purpose, knowledge &amp;
  vision of things as they actually are as its reward. Knowledge &amp;
  vision of things as they actually are (yathābhūtañāṇadassanaṃ) has
  disenchantment as its purpose, disenchantment as its reward.
  Disenchantment (nibbidā) has dispassion as its purpose, dispassion as
  its reward. Dispassion (virāgo) has knowledge &amp; vision of release as
  its purpose, knowledge &amp; vision of release (vimuttiñāṇadassana) as its
  reward.


According to the Yuganaddha Sutta (AN4.170) spoken by Ananda, insight can be developed before concentration, or concentration can be developed before insight, or both can be developed in tandem.

However, in the AN11.1-3 suttas spoken by the Buddha, the chain of causes starts with virtues (sila), and passes through rapture (piti), pleasure (sukham), concentration (samadhi), then goes to "knowledge and vision of things as they actually are" (yathābhūtañāṇadassanaṃ).

To my understanding, "knowledge and vision of things as they actually are" is the goal of vipassana (insight), right?

So, I take it that AN 11.1-3 implies the following sequence:


Every person (monk or lay person) should start with the cultivation of virtues (sila) - the starting point for virtue according to other suttas is the five precepts
Virtues (sila) eventually leads one to rapture (sila), pleasure (sukham) and concentration (samadhi), which is the goal of samatha (tranquility) meditation.
Samatha (tranquility) meditation then leads on to vipassana (insight) meditation
Vipassana (insight) meditation results in the "knowledge and vision of things as they actually are"


So, is my interpretation correct that the correct sequential order of practice is first sila, followed by samatha, followed by vipassana?

On the other hand, MN 149 does say:


  Thus for him, having thus developed the noble eightfold path, the four
  frames of reference go to the culmination of their development. The
  four right exertions... the four bases of power... the five
  faculties... the five strengths... the seven factors for Awakening go
  to the culmination of their development. [And] for him these two
  qualities occur in tandem: tranquility &amp; insight.


So, which is the right interpretation?


The one in AN 4.170 stating that insight before tranquility or
tranquility before insight or tranquility in tandem with insight, are
all good.
The one in MN 149 stating that tranquility and insight happens in tandem
The one in AN 11.1-3 stating clearly that virtues should come before tranquility, and tranquility should come before insight?
As I explained in "Is samatha meditation more suited to lay people than vipassana?", the factors of "being good", "feeling good", "calming down", "understanding", and "liberation" are designed to support each other.

In Mahayana, it is generally understood that the exact path depends on the student's propensity. 

People of intellectual type are better suited for "understanding"-first paths.

Simple people caught up in the drama of life, are better suited for "calming down"-first paths.

For most people in between these theoretical extremes, there is a mixture of "understanding" and "calming down" developed in tandem, with slightly more accent on one or the other, depending on exact situation.

For people of extremely brilliant intuition, there's the fourth path of cutting through directly to suchness. Again in real life these "extremely bright" students do not exist. There is usually some combination of study and practice required to remove all doubts.

The general principle here is that the coarsest / biggest / most obvious obstacles should be removed first. I think it was Thrangu Rinpoche who went as far as to say that we should work on them one at a time, completely focusing on the worst mental/emotional/behavioral issue until it's resolved, before moving on to next.