Comfortable seating.

Am incredible birthday cake

Signature cocktails. Also, you could provide a signature alcohol free cocktail (there are tons of AF options available including the brand Ritual "liquor"). Garnishes garnishes garnishes, and you can never have enough ice

Lemon infused water in a big drink dispenser for self serve.

In addition to handing out food, consider a side table with self serve charcuterie

Maybe an area with some kind of props to take fun pictures (funny glasses, mustaches, boas) depending on the vibe.

Bathroom: get a large pack face towels (from amazon cheap) roll them up in a basket, basket on the floor for used ones + candle

Please help me throw a fabulous evening cocktail party. Birthday person doesn't want a party at a restaurant.

So far I am thinking hiring a bartender to serve, wines, prosecco and a few easy cocktails. I will have the menu printed for drinks.

For food a lot of finger food and hiring a few people to offer to guest while they are mingling.

Nice music in the background. Anything else I should think about?
Thanks