Can I get a pink ID card with a DTV visa in Thailand?

If you want to go for 90 days, then I would suggest a Single Entry Tourist Visa. You get 60 days and can extend in Thailand for another 30 days. SETV cost $40 USD and the extension is 1900 baht if you do yourself or 4000-6000 with an agent.

You should be able to do this twice a year without a problem. Besides the fees, the only money requirement is you need 20K baht worth of currency (yours or Thai) to bring with you.

Yes, no problem. You can apply for the non-O visa and spend 90 days in Thailand. Return home and then apply for another non-O for a different trip at a different point in the year.