sawasdee khrab. Yes, ThaiPass will not accept PDF, so just open your document on your phone and take a screenshot. The screenshot is the same as taking a picture, it creates a JPG. For each required document submit your JPG copy. You should have no problem. Cheers!
Haven't used deemoney so not sure how their rates compare. I use Wise about $9 to transfer 37K but they give really good conversion rates. Money right into Thai bank account, often w/in a minute.