What? You think it's easier to stay in the US long term than Thailand? Attempt to stay in the US anymore than 6 months as a tourist and see what the result is. That's if you manage to get a 6 month stamp to start with.
Thailand is easy to stay and has many options for being here long term. Staying here on the wrong visas and swapping passports is simply starting to be not tolerated any longer.
If you get the extension on that visa before it runs out, then you would need a reentry permit to keep the extension alive. I guess your visa itself, actually runs out this month?
Forget being stamped in until April if you leave again and don't return until after October when your visa is finished. Your reentry permit will only be issued until your visa finish date in October.