I stayed at Pullman G some years ago, it's outside seedy Pattaya on Naklua beach, lots of restaurants walking distance, quite neighborhood.
Beach itself not clean but anyway better than Pattaya bay, hotel has good food, they had a Wednesday Spanish tapas thing with guitar music/songs and excellent Friday seafood buffet.
I always stay in Accor properties because the are child friendly but only have 1 daughter of 8 (am gold and often get upgrade)
for October I booked Novotel Phuket Surin Beach, I had it with Pattaya.
With 5 pax you might wish the family suite with bunk bed, pricing I see for 4 nights is 19.280THB or 626USD

But for a family beach resort near Bangkok I would rather chose Bang Saen closer to Bangkok.

As for Bangkok any of the many Novotels would do, Citadines no Thank you, Novotel Ploenchit would be a better location.