Just to report back, I reached Ekkamai just before 7.00 am yesterday (Monday) to make sure I could get a seat on the first bus at 8.00 am. However I was 'persuaded' to take a 'lot tu' departing in a few minutes for 140 baht. This was a bit faster than a normal big bus even though it passes through the Chonburi main drag and drops off and picks up. Also it travelled all the way down Sukhumvit in Pattaya down to Chaiyapreuk road which is where I wanted to go anyway.
No checks, no problems. Coming back I caught lot tus' as well as they are easy to flag down anywhere on Suk road.
I did not stay in Pattaya itself so no info on hotels etc.