Thank you both so much! Off to try these great suggestions :)
edit: oh just thought of a quick fix for overly inquisitive/ambitious sims pyromaniacs which the game loves spawning (typically with Cook Skill = -1 to 0) for explicit purpose of trying to access any venue areas with a stove:
JUST LOCK THE RESTAURANT KITCHEN DOOR. Lol. Use the lock door feature to exclude all Sims except your active sims who have a cook skill > 5. Problem resolved. Lol
So seems leaving it designated a Nightclub by default (with locked kitchen door) is the best way to go. This way 99% of the venues will work as intended (minus the retail clothing/pet stores etc which are strictly for atmospheric purposes). And both active/non active Sims can autonomously eat at the bar if hungry. So whenever my Sims need to dine out formally, I'll just temporarily change the lot type to restaurant.
