One side note: The application fee can only be paid at the embassy in the morning between 9 am and 12 pm. Arrive before 9 am to shorten your wait - it can get quite hot.
1) Yes, you should print out the visa once you receive it. This is important information, as the process is not yet fully digital. I would also like to mention that I had to show my visa again when I entered Thailand the second time (day 29).
2) I just checked our passports – our DTV stamps are stamped for 180 days. 🚀