Can I get a Residency Certificate with only 30 days of accommodation for my Non-Immigrant O Visa?

Go to the bank and ask for requirements to open. I was not asked for a certificate of residence and was able to open two accounts - I like keeping the 800K+ separate.

Most immigration offices only need the TM30 to get the certificate of residency.

And you're not going to be applying for any further 90 day visa. You ALREADY HAVE the 90 day visa. The only option you have now is applying for the 1-year extension. Unless you're married to a Thai or have a half-thai Child, the 1-year extension is the only option for you.

You need to get a bank account opened and get the 800,000 baht transferred into the account in the next couple of weeks. If you're not able to do that, you won't have enough time to meet the seasoning requirement for the extension. The financial requirement for the 1-year extension is that the money must be in your account for 2 full months already at the time you apply for the extension.