We just had our first friend party last week, also for the big #5.
We had way too much time!
And they didn't care about eating, even though it was cake and ice cream.
So I'd ditch the drink/snack idea entirely.
I don't know why you don't want to open presents. That was the kids' favorite part, and it gives all of them a good opportunity to learn manners. Talk with your child about saying thank you, and what to say if he doesn't like it, and what to say if he already has the item that he receives.
And honestly, that was their favorite part of the party! We warned them ahead of time that we would not be able to take the toys out of the packaging, though (that would have been mayhem), so they'd have to come back for a play date another day. The best part was that after the presents were open, they started throwing all the tissue and wrapping paper in the air, jumping around and laughing. It was GREAT! After a few minutes of that, we had all the kids race to see how fast they could shove all the wrapping into a big box, so they cleaned it up by themselves.
I think kids will be supremely disappointed to not see their friend open the gift from them. After all, that's a basic part of most birthday parts. Sing Happy Birthday, eat cake, open presents. Everything else is just a bonus.
We had a craft to do, and wow, did they love that! My husband and I were the only adults, and it was a little hectic at first, but the kids had so much fun, and loved their rockets.
We also played a version of pin the tail on the donkey, tailored to our party theme.
I don't think kids that age will be good at guessing candy in a jar, unless you do a small jar with large pieces of candy, say about 10. I also don't think they understand why somebody would get a prize and not everyone. We didn't have a prize for our game, except announcing that everyone did really great, and Tanner did it best. That was enough, seriously! They were already on to the next thing by then.
I wish we'd had more games planned, because we ran out of things to do and still had time before parents arrived. It's easier to have lots of games planned and have a few go un-played than to end up with empty time on your hands while the kids run amok.
Here's an idea for a craft, but it will take some planning. Let the kids decorate their own goodie bags. Just have stickers and crayons or washable markers and let them draw on a white (or even brown) paper sack and write (or help them write) their names on them. Then have someone working on slipping the goodies (you could have them already split up in baggies) into the bags while you're serving cake or opening gifts.
Another thing to remember is a piece of paper to write down who brought which gift so you can write thank you notes.