You can get a DTV via rental property management. You need to show how you manage the business online. There is no minimum income requirement. You can find several posts in the threads from such DTVERS.
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