I can't defer the pension.
So you have the pension, whether you want it or not, and it will cover living expenses. At least for now, if the pension does not have a COLA, and maybe forever if it does. In either case, your option #3 looks good, but we are looking only at part of the picture.
If you put all inputs into
www.i-orp.com, what does it suggest in terms of Roth conversions?