I haven't read "everything" but I've certainly seen the majority of people saying you will need to do a 90 day report, just like all the other longer than 90 day visas.
If you leave and come back there is no re-evaluation of your DTV credentials. If you extend in Thailand, you are basically applying again and need to re-submit the paperwork to get approved and hope it still works. I'll be leaving before 180 days for the next 5 years so I don't have to stress about this.
No, I'm Canadian and don't need to move money to Thailand for visas as we can get affidavits of income from our embassy/consulate. It's just cheaper and more convenient with fewer visits to immigration and free multi entry.