only government operared services as you are required to give them an Thai ID number for track and tracing purposes and most foreigners do not have a Thai ID card but if you do have a pink ID card you can use the bus.
immigration office differ in the way they implement rules. In my present and previous area they do/did not ask for the proof that the funds have been transferred on monthly basis. That is why it is better to talk to your local immigratiom office.
non imm b is granted if you are married to a Thai or not. The non imm o based on marriage is linked to your relationship to a Thai. Thus your visa dont only depend on your business making a success but also your marriage. Purely from a business sense the non imm b is beter and more stable option for a businessman, which the OP seems to be. As for the changes to the non imm o based on marruage I did say I dont know if its still going to happen. I just repeated what the IO said. As can be expected he did not go into details. Lets wait for this week as the scheduled date was the 22nd April 2562 for these changes.
I had a chat with my IO last week, before BJ was moved amd he said that they want to bring in changes to the non imm o marriage visa. I domt know if it still will happen after the change but for me the non imm b is more stable and not relying on the longterm stability of a marriage.