Minor update. So far (in this portion of the challenge) all flights I checked in for had my FF number on the boarding pass without having to talk to the agent (and all recognized Skypriority status). Seems like as long as the airline is using Amadeus (and not some homegrown IT), things work correctly at check in.
RO - flown, status on bp, credited (4 days)
KL - flown, status on bp, credited (4 days)
SV - flown, status on bp, credited (under 24 hours)
GA, VN - planned tomorrow (status on bp, was able to select "premium" seats on both, at manage booking for GA, at check in for VN)
CI,KE - planned day after (status on bp for KE, on confirmation for CI, but must get paper bp)

P.S. encountered one person doing the challenge on my SV flight (he was explaining the challenge to someone else). I introduced myself, but he did not want to be buddies

P.P.S. Updated RO