if you came in on a 90 day non o based on marriage, they are probably not going to sell you another one. They will expect you to apply for the one year extension based on that visa.
khor ror 22 is only for if you were married outside Thailand, and then had it registered in Thailand. If you got married inside Thailand, the one you need is khor ror 2. Same same but very different.
There's no real answer to that besides what the IO you are going to stand in front of thinks about letting you in again. If it looks like you are trying to live in Thailand on visa exempt entries, you are getting stopped sooner rather than later. If it doesn't look that way at all, you might never even experience being questioned about it.
He needs a non B visa and a work permit. Visa comes first. They should provide him with all required paperwork to apply at the Thai embassy*before* he travels, as he won't be able to work legally without it. He *could* just travel on over and then sort it, by going to a neighboring country for the visa at a Thai embassy, but he would not legally be allowed to start working on a tourist visa or visa exempt entry. If the employer wants him to start sooner rather than later, or if he depends on getting paid from the get go, it's better to have the visa before coming here. In tandem with the visa they also need to provide required paperwork for a work permit. If they are not willing or able to provide all the required documents for these two things, run away.. Not worth it to work illegally and risk deportation/fines/jail time.
your window to apply is from 45 days before up until the last day. No matter when you do it, you would not move the date of expiration at all. It will be exactly one year on top of your current expiry date.
You can be a munk on any visa. Just like you can study on any visa. The time restrictions will of course depend on what visa you have, and the "stay until" stamp in your passport. You can't get a non b if you are not working, but yes, you can work on certain other visa types too. For example the ones based on marriage or kids.
it means you have to get a separate original RC for everything. It is made for a single purpose, and can only be used for that. You cannot use the same one for different things. You can however get and use just one if you for example are applying for both motorbike and car license at the same time in the same office.