Hi, I'm brand new to all of this and still trying to figure it out. I definitely didn't expect wedding planning to be as complex as it is, and I don't know what the hell I'm doing with any of it. But, I've managed to pick a venue, date, and colors, so I guess that's something. Now, my fiance and I are trying to think of food, and I'm even more lost than with the venue.
It's going to be a very small wedding (I'm estranged from most of my family, and neither of us have a ton of friends to invite), probably between 25-30 people, if that. It's in a barn (we live in East TN, and it's a pretty rustic wedding), and there's not many options near the venue, cause it's in the middle of nowhere. So, we're thinking about doing our own food (or having his dad do it, he's a chef), but I don't know what to think about making. We thought about different kinds of sliders (like a build your own station), but everything that I've seen says that sliders are an appetizer, not a meal. We were going to have mac and cheese and a couple of other sides too, and then dessert (including a s'mores bar), but now I don't know if it would be enough.
It's a very causal wedding, and most of the guests are going to be his family, and a few friends that we've known for years. The most "formal" guests are going to be a few people that he works with, but they're very laid-back. We don't want a formal meal, just something that matches the vibe.
And, we're not serving alcohol. He's not going to be 21 (the wedding is a few months before his birthday), a few of the guests can't/don't drink, the place is pretty remote and I don't want anyone drinking and driving, and since there would only be a small number of guests drinking, we figured that it would be best to save that money. We are gonna have a good amount of sweet tea and lemonade though

I don't know what to do, do you think that the menu is okay, or that I should change it?
Re: Menu??
Since your soon to be FIL is a chef, I would ask him if he can recommend any local caters or chefs who won't be at your wedding as guests. Most caterers will be able to take care of all the prep, set up serving, dishes, silverware and break down/cleanup after. Once you find a caterer, then ask them to make recommendations for their best dishes in line with the type of casual meal you're looking for.
If you really don't want a meal, the other option is to go with a non-meal time and just get some grocery store platters to serve snacks. As long as you find things that can be served room temp, it's easy to set up ahead of time. You'll just need to plan to stick around and clean up after, or hire someone for just that piece.
I highly recommend a buffet set-up for the kind of reception you are talking about. I think sliders with some sides like mac 'n cheese are fine and enough food. But it's a good point that those might be a difficult entree option because they are typically made fresh off the grill.
I agree with @MyNameIsNot that you shouldn't expect...or even accept his help if it is offered...your FI's dad to be responsible for the food. Though he would be a great resource to use for either recommendations and what are tasty and easy entrees to serve. PLUS...most importantly...handling the food safely at all times. Both for transport to the location, while it is stored, and while it is sitting out.
That's fine if you all don't want to serve alcohol. That sounds like a good idea and a good cost savings, considering your guest list. I assume lemonade and sweet tea are just examples of the beverages you all will have. But jic, for the love of all that is holy, do not have those be the only choices, lol. A lot of people either can't drink or don't want to drink beverages that are loaded down with sugar. At the very least have bottles of water also. I would also suggest unsweet tea and soft drinks (diet and regular).
And yes, we will have other drinks, but sweet tea and lemonade are probably going to be the ones we'll have the most of, just because I know that almost everyone that's coming prefers one of them over soda, but we'll also have some soda, water (I prefer water over anything), and some unsweet tea (even though it's blasphemy in the south)
If you don't think anyone would drink it, as long as water and soft drinks are an option it's probably fine to not have unsweet tea. I just think of it as being as easy to make some unsweet tea if you all are making tea anyway.
I'm including a little story about the first time I tried sweet tea, because I think it's amusing and a fun look at regional differences. I grew up in CA and sweet tea doesn't exist there. As in, if you order iced tea in a restaurant or fast food place, it is automatically unsweet team and they don't even have a sweet version. I didn't even know what sweet tea was until I was in my early 20s and moved to New Orleans.
I went to a Popeye's and ordered iced tea. Here was the conversation:
Cashier: Do you want sweet or unsweet?
Me: Sweet? What is that? Like, do you all already add sugar to it or something?
Cashier (looking at me like I am a crazy person): Yeeeaaahhh
So I tried it because I'm an adventurous eater and almost started gagging. I thought it tasted so bad and was way too sickly sweet! I've occasionally tried it other places. Sometimes on purpose just to see, but usually on accident because they accidentally gave me sweet instead of unsweet, lol. I've never found one I liked.
Another regional difference. The first time I ate fried chicken with the first NOLA b/f I had. Me (looking horrified), "You put ketchup on your fried chicken! I've never seen or heard of that before!" Him: "You DON'T put ketchup on fried chicken?!?!" LMAO.