For drinks I would keep it simple - red wine, white wine, beer and soft drinks. Maybe some fizz but don't start doing cocktails/spirits. You'll know your friends/family better than us - for DH's side of the family I'd be working on the equivalent of a bottle of wine each over an evening; for mine we'd be running out of tea bags.
I think Majestic Wine do free glass hire and sale or return which might be useful.
Put everything out on a table/worktop and encourage people to help themselves so you don't have to be waitressing.
For food I would generally go for bigger quantities of fewer things rather than trying to give lots of options. Sandwich platters are easy to order, you could add some big pork pies, quiches, lots of crusty bread, maybe boiled new potatoes and a couple of big salads (coleslaw, couscous, potato salad).
If you are more adventurous you cook cook a couple of big hams or a couple of sides of salmon to go with salads/bread/potatoes.
Plenty of big bowls of crisps/nuts/snacks if people are drinking.
If you're having a birthday cake that could be dessert. Or maybe some big cakes, cheesecakes, brownies etc.
Final advice would be not to overthink it. Do as much as you can beforehand and try to enjoy the party with your DH rather than rushing around cooking sausage rolls and topping up drinks.
On a practical note - buy plenty of napkins, black bags, kitchen roll, wipes, toilet roll and disposable plates/cutlery.