Your fare is ACLA, which books into M if the feeder flight does not have premium cabin. Class A is the cheapest premium class. (W books into I, S books into B, and A books into M on flights without premium)
For your mileage earning, both class A and M are 150% on its own programme for fare ACLA, however as you are crediting to a partner, the partner should only be possible to see the letter M for the feeder, which means economy.
It should be possible to select your seats for your ticket online, where I did it on an SCLA/ACLA ticket bought online before (however I have refunded the ticket because I found some cheaper offer in class Q discount economy in another port).
There is a bottleneck transferring at SVO where an officer looks (but not stamp) at your passport, but 2 hours should be enough for international to international connection.