You have to ask your local immigration office as those requirements vary. Some offices require you to bring your passport only, while other require more documents.
You better have TM30 receipt.
These general documents you need for the first 90 days report:
- copy of Passport ID, stamps, visa pages. and original
- TM30 receipt
- filled TM.47 original
- copy of departure card (TM.6) (if you entered by land)
Single re-entry permit fee is 1,000 baht, multiple 3,800 baht. 200 baht Service fee might be charged at the airport if you don’t have application documents. Get whichever suites you.
no, you cannot have more than one valid re-entry permits at once. However, no downside to ask the officer you want to apply for two permits with two sets of the same documents. the worst thing would happen is he says no and you get one permit.
Yes, you can get a re-entry permit before you leave Thailand to keep your current stamp 'alive'. You will be stamped in for a whole new 90 days when you enter 2 April. You will be stamped in again until the same date.