Marriage certificate also needs to be translated before legalized by Consular Services. I'd recommend using a translation services that can get everything done for you, saves time and stress. My IO didn't require Kor Ror 22, the legalized documents were sufficient.
My IO added the under consideration from the date my 90-day stamp ended not from the day I applied for the extension. When I go back on that date they stamp me in for the remaining 11 months.
For what it's worth this was how I did it for marriage registered in NZ. 1. NZ marriage certificate legalized by MFA in NZ before coming to Thailand. 2. Visit NZ Embassy in Bangkok to certify. 3. Down the road to Express Translation Service who arranged translation, processed with Consular Services and sent to me at home address (I was happy to pay them to save me running around doing it myself). Around two weeks to receive everything. I believe they can assist with getting your Kor Ror 22. Our immigration office didn't require Kor Ror 22 even though it was on the handout of required documents, the translated and legalized marriage documents were adequate but that's office specific I guess.
Opened with Kasikorn in Big C Nakhon Phanom a couple of weeks ago. Passport, Non-Imm O visa, foreign marriage certificate translated and legalized, yellow book (we own our own home), wife's blue book and ID card. Think that was about it. If you're renting take your rental agreement, residency certificate. If you have a Thai driver licence that'll help. The more you can bombard them with the better, they'll likely photocopy everything you offer whether they need it or not. Not much else you can do really short of using an agent if you're in one of the main areas.
Seems a bit back to front in that they went ahead and finalized their plans then asked if they're doing it right. Logic would suggest you do your research, come up with a proposed plan and then by all means run it by the group. I wish them luck.