It seems to depend on which office you go to. Last time I renewed mine it was 7 weeks before expiry - at Sri Racha Immigration (they told me it was possible up to two months before). I understand some other offices say only one month.
No, there is no requirement for money in the bank. The "million dollars" I think you are referring to is not a million dollars, but 1 million Thai Baht, which is the cost of a 20 year Elite Visa (a 5 year visa costs 500 THB). This is not money in the bank, it is the actual price you pay for the visa. As mentioned earlier, there is currently a 6 month "bonus" on these visas.
Take your Passport, Departure Card, 90 Day Notification form (TM47) plus copies of each of them (Face page, last arrival stamp and visa from your passport)
It seems to depend on the individual branch, not on the bank itself. I opened an account absolutely hassle free at KBank in Sri Racha (on the advice of an Immigration Officer in Sri Racha)