Agree talk to a reputanle lawyer who is focused on company structures. Too many ways your company can be deemed invalid if it doesnt have a real business generating income, employee questions, file audits tax returns etc. Also can be problems if you try to setup preferential voting rights to maintain comlany control even with 49% share ownership.
Not sure what visa and extension you are talking about. As far as I know; All tourist visas are for 60 days in Thailand (unless you are talking about the special STV that gives you 90 days at a time but that program is ending soon). Also the only extensions for 60 days are for visiting family (if you have a Thai spouse or child) or currently cannot travel due to Covid extensions (again that program will end before could help the OP). Regular extensions for tourist visas are 30 days.
They did when got mine done, althought that was years ago. If Ibrecall correctly they didnt authenticate the marriage certificate per say, but signed and stamped a letter we wrote saying we were married and this was an copy of our authentic marriage certificate.
If you use 800k banked money for an extension of stay it does not have to come from outside Thailand. However if you are using 65k per month (12 months) then the money has to be transfered from outside Thailand. Also if you apply for a nonO retirement VISA inside Thailand then the 800k banked money mist come from outside Thailand.
Samat Prakan follows the correct rule - 2 months before date of application and 3 months after. Also need over 400K ballance the rest if the year Actually I do t think I have heard of an office using a different rule for cash seasoning but I suppose ot could happen.