Dont think that would be acceptable.
A few months + prob OK. 10 weeks doubt it.
Only the immigration office can answer that.
No insurance required for Non O obtained inside Thailand or outside.
The docs are basic. The main one is the 800k in bank.
Funds from abroad.
Rest is minor. TM30, map, etc
Hopefully the DTV will come through.
Edit: my first ever Non O retirement, I had to obtain at Vientiane since I could not show funds from abroad for Non O application inside Thailand.