immi in Udon Thani don't ask for tm30 - they just check it online. 3 times I've got a proof of residence without a copy of my tm30. But of course a very good idea in general to bring it.
not really - any branch can do the paperwork. My Bangkok Bank account is in Pattaya and I went to Bangkok Bank in Udon Thani for the documentation for immi for my extension. Of course no problem
seems you skipped some words during your reading - wealthy was mentioned in the original post and wealthy is mentioned in the description of the LTR included in another reply