okay, well I'm sort of a party crazy person, so maybe you should take what I say with a grain of salt...but..;)...I think you should have fun! My kids are exactly 2 years and 7 days apart and I'm doing two separate parties this year! Yipes! :)
I think the ponies would be great in another year or two, but hoenstly, right at 1 and 2 I think they might be really scared of the ponies, plus you'd have to hold on to them the entire time. Probably at 2/3 or 3/4 would be even better. I don't think you necessarily have to have games but sometimes I do crafts. I would start with picking a theme b/c then you can really focus your ideas. Oriental Trading Co has great ideas for crafts and party favors. My daughter's 2nd b-day was a golf theme and the kids made their own golf visors (foam with foam stickers) and put on sports tatoos. Then I just had a ton of toys in the back yard and they entertained themselves. But, really, a craft isn't always necessary. It depends on the ages of your kids really. Tatoos are always a hit, so that's an easy one.
I would also suggest doing cupcakes only b/c then you don't have to stand there cutting the cake forever. Your party seems smaller, so it might not be a huge deal, but if you'll have a lot of adults plus 10 kids, go for cupcakes...it's easier. Costco has AWESOME cakes and cupcakes and they are super cheap. I buy those and then decorate them myself according to my theme. Costco won't do any decorating but they're so good and so inexpensive that it's fun to add some touches to them yourself.
As far as the parents, I would just have enough food and chairs for them to sit, chat and watch the kids. We are also having beer at my son's 1st party, b/c really, it's more about me than him at this age and I'm okay with it! Plus, it's more of a family and friends backyard bash b/c he doesn't really know it's all about him yet! Some people certainly probably disagree with me, but that's okay. We do juice and water for the kids and iced tea and beer for the grown ups! People know and respect that it's a kid party and no body ever has too much!
If you want more crazy party ideas, feel free to ask! :)
**I also was going to mention to look into bounce houses and stuff...they are less expensive than I thought they were and you get to keep them for 8 hours usually so your kids can play with it all day long! I don't know your budget, but since you're combining it might be a bit more. We didn't get a bounce house but I did get a balloon artist for this year and everyone is really excited!