As discussed, Transcript is best.
IF you dare to provide the Federal tax return copy, it can't be just the 1040 which is only a few pages and not complete. They need the whole thing. All pages and schedules and including all proof of earnings... so W2s for employed and 1099s for self employed.
As above, a 1099 is a earning statement for self employed. Are they?
Offer letter, no.
Current employment letter, yes.
And that projected income amounts listed on it is your current income for the I864.
Instructions state 6 months. Ensure you have read them.
See above.
Only if you are using assets because your income doesn't meet the FPGLs.
Does your income meet it?
Then don't use assets.