Do dads and best man have to match groom?

No. Nothing "has" to be a certain way. Depends on the kind of look you want and what people are comfortable wearing/spending.

We went to a wedding where Groom wore tails but no one else did.

Nope! My guy is wearing a tux, the boys are just wearing matching ties. My dad isn't matching anyone lol. Best wishes!

No, they don't have to rent tails unless that's the look you're going for.

The only guideline I've heard is that no one should be dressed more formally than the groom - for instance if FH is wearing a suit, his dad shouldn't be in a tux. Since nothing is more formal than a full coat and tails, I think you're good there!

No

Nope. And actually my FH said husband is supposed to wear something a little different from everyone else to distinguish himself. Not sure if that's true but I like that idea nonetheless. I think FH was going to do a different jacket and a bowtie instead of a standard tie.

No. My FH has a tux that no one else has. He and his BM have the same vest, and the other GM have the same tie. Other than that it's different.

Nope.

My FH wants to wear a charcoal gray tux, so the groomsmen/best man will wear them too since they are pretty straight forward. My dad will probably just wear a suite (unless he chooses to wear a tux also?)

I'm also thinking of including my brothers by having them walk my mom down the aisle...They will also probably just be in a suit.

I think you can do whatever you want. My Dad wants to wear a traditional black tux with bow tie. FH is wearing black tux with a tie. We are not having a BM but GM's are wearing black tuxes with navy blue ties and vest. RB may wear a tux like groom. It's his son so I think that will be cute.

No but you may want to check if FH feels comfortable with guests wearing tuxes if the groomsmen are going to be in suits. That way if people ask, you can mention that it's not black tie. I agree that if you're going with tails for your FH that the groomsmen should be in tuxes with or without tails or it may look a little weird.

No they don't have to match. My dad is wearing a black tux and the groom and groomsmen are wearing navy.

Nope. The dads aren't matching the groomsman.

You can do whatever you want, but I do think @Liz's guideline is great - no one should be dressed more formally than the bride or groom!

It's very common for the groom to be wearing something different of more formal that the rest of the groomsmen! I also agree with @Richard that if the groom is wearing tails that the groomsmen should be in tuxes or black suits!

Tails are very, very formal (like black tie wedding formal level). The other men don't have to match, but they should definitely at least be in black tuxes to match tails.

Not necessarily, I think they can get away with regular tuxes. I also agree that tails are for extremely formal events.