Make life easy for yourself. Apply for the 90 day Non-O visa before coming to Thailand. You can then open a bank account easily and deposit the funds for the 12 month extension of stay
A DTV is not suitable for you if you plan to work inside Thailand. You need to first find a job then apply for a Non-B visa and work permit with support from the school you will work for. As most schools expect you to apply for the Non-B outside of Thailand and you can't have 2 active visas the DTV will prevent you applying.
Your daughter could apply for the DTV if she will work remotely from Thailand, but not if she will work for a Thai entity. Once she has hers she could apply for her daughter as her dependent
Was his application at the embassy in Abuja? He could try elsewhere but many embassies take at least a month to process applications from Nigerians and require police certificate authenticated by both the Nigerian Ministry of Foreign Affairs and the Thai Embassy in Nigeria
Yes. Not available after 7 days although immigration may be able to see it. If they want you to provide a receipt you'll have to get your landlord to resubmit and provide you with a copy of the receipt
so many things getting mixed up here. Do you have a Thai SIM registered in your name associated with your bank account? If not that is likely your issue. Go and visit your mobile service provider and get the number in your name then go and speak to your bank
I think that most people with genuine accounts have nothing to worry about. If you had an agent open an account for you that's different, in which case I'd recommend you take your passport and go visit your bank branch and talk to them