generally speaking term deposits are not acceptable, they want to see instant access accounts. If the term deposits can be terminated early, even with a penalty, they might be acceptable
The only time I've heard of a spouse having an issue was when they tried to extend at an immigration office inside Thailand and their other half hadn't extended
The law is pretty clear if he doesn't spend 180 days inside Thailand in the year he brings the money in there is nothing to worry about. If he does spend 180 days in a year inside Thailand then assessable income is liable for Thai tax. He would need to look in the DTA between his country and Thailand to determine what constitutes assessable income, and also whether he can claim any tax credit already paid on the assessable income in the same period
The earliest you can do it is when your funds have been in the bank for the required time. The latest you can do it is the day your visa expires, although not recommended to leave it that late
Anonymous participant 445 that's not true, it is issued for a purpose. That's like saying you obtained a Non-O visa and you can use it for whatever purpose you like