Can a developer change the minimum payment threshold? Is there a way to change the minimum payment threshold generated by inApp purchases?

Google allows to change the minimum threshold (i.e.: 3.000€) and also to postpone the payment till 1 year.

This is very useful for starting indie studios in countries with a bad entrepreneur tax policies. Even a small invoice will force the studio to pay 600€ taxes per month to remain legal.
No, you can't change the payment threshold. It'll always be either $10 USD (if your currency is supported by Apple), or $150 USD (if it's not).

Source: iTunes Connect > Resources and Help > Getting Paid


  When will I be paid?
  
  Payments are made within 45 days of the last day of the month in which
  book purchases were made. To receive payment, you must have provided
  all required banking and tax information and documentation, as well as
  meeting the minimum payment threshold.
  
  If your bank and bank account currency is listed in this table, you
  must exceed a minimum payment threshold of $10 USD. All other bank
  countries and bank account currencies must exceed a minimum payment
  threshold of $150 USD.