only if you want to extend in Thailand. You don't need to show anything for re-entries, it's a five year multi entry visa with unlimited entries for the five years and once you've got it, you've got it for five years. It's not like a retirement extension where you have to justify yourself every year, it's five years.
you have to do 90 day but it may never come up if you don't want to do an extension and don't need anything else from immigration as they don't check 90 day reports at the airport.
this isn't the case, it explicitly states in the Royal Gazette announcement stamp is for 180 days BUT not more than the validity of the visa. Used be the case you could use this trick to get another year out of Elite if you enter on the last day but they changed that too a few years ago, now 5 years = 5 years.
no, but MFA were quite confident of this and it's how other multi entry visas work, they don't require proof again at the point of entry. Several people have already re-entered second or third time on DTV and all of them have been stamped in with no questions. Anything could happen in the future but all indications are they are not requiring anything on entry but the visa.
MFA have stated extensions will probably require showing proof of the 500k again; it's up to immigration. The visa though is a multi-entry 5 year visa and doesn't require any proof to enter, this is how multi-entry visas work. MFA have stated that and people have already re-entered a second time and confirmed they didn't need to show anything.
you don't need to show anything except the visa on re-entry. MFA were very clear on this, it's how other visas work and we already have people who have re-entered and confirmed they didn't have to show anything. It's a five year multi-entry visa.
Thai bank accounts don't inherently have annual fees, if you get a savings account with no card there are no fees. If you get a debit card it's ~200B (£4.50) for the card, which is really nothing.