If you want to stay a year or more you will need a long term visa. If you're 50+ then look at the Non-O. If you're under 50 then your options are more limited unless you want to splash out on the Thai Privilege visa. For close to 9 months with a couple of border bounces look at the Multiple Entry Tourist Visa
They claim to process applications in 5 working days so 7 days may be a bit tight if they ask for additional information. That resets the clock at some consulates. I'd definitely recommend staying there until you know the outcome
Simpler to apply using one of the soft power options, income is irrelevant you just need to show you have the 500k baht or equivalent in your bank account
I guess you could go to a nearby embassy and apply for a non-o there but you're still going to need money in the bank, although you might be able to use your home bank. You could then open a bank account and transfer the money in for the extension. But if you don't have the money anyway then you'll need to find an agent to accommodate
but when you apply for and are granted a new passport from your home country it will contain the details on your old passport in the biometrics. Similarly if you have 2 passports due to dual nationality. The biometrics embedded in the passports will have details of the other passport