Mine took approx 5 days from Hanoi embassy and arrived the day after I got back to Thailand. I then did a border bounce to activate the visa. Not the ideal method but it is possible. Can you not change your return flight?
I dont think they are wanting all those documents only the ones marked Essential. It all depends what you stated to them as employment I guess. Just my take but good luck with it
Does it not go live(the necessity to have TDAC) until 1st May? And you are questioning what to do if possibly maybe the site is down for 3+ days nearly 1 month beforehand? Think your head needs a wobble