There are several posts from Manilla applicants in the threads. It is ok to transfer from a Time Deposit to a personal savings account. You need to check with Manilla if they have a seasoning requirement before applying
Anonymous participant I would just use my name applying as a freelancer. Applying with a business name will likely lead to a business registration request. Laos, Vietnam or Indonesia are great options.
There are a few embassies in America who approve via such accounts. You can find such approvals in the threads. The vast majority of embassies worldwide require it in a personal bank account.
You are free to explore Thailand as you wish. To renew your stay at immigration you need to present a new contract. There is no requirement to voluntarily show a contract upon arrival from a border hop. The airport IO can ask to see evidence of activity though
I submitted all 3 for my application but different embassy. I guess you could just do 1 and 3. Important to show work payments received along with the 500k.
You can apply in one country for the DTV and enter Thailand with your kids. To obtain add on DTV for your kids you must apply outside of Thailand. Very likely your money is enough as your kids are very young.