When I studied Thai I got grants/loans from my government for the time I was studying, just saying, there are ways to get money without working while studying here, how depends on your nationality/government policies.
You should be fine. I have been at thammasat for 4 years. And although i personally don't use a ED visa many of my peers are, and they have had no issues what so ever since it's a registered known university and not some shady Thai class that may or may not occur when stated.
I know I have transferred it before, i think i paid 500 baht though. But if it's not necessary and I can bring both passports to the embassy in savanakhet together with the letter from my embassy then surely that would be a preferable option rather than sitting in a queue for hours at CW. But wouldn't wanna risk it unless people know it's doable.