Is 4pm too early?

I don't think I'd feel too weird about it. If that's what you can do, that's what you can do, even if it's a bit early.

Maybe you could do a rehearsal brunch before-hand?

I don't think so! You could even do dinner at 5 and just let people hangout for an hour or so. Our venue only lets us do 8 AM rehearsals the day before unless there isn't a wedding (and there usually is).

I think your overthinking it. People know it's a rehearsal, and afterwards you eat. As long as you give them more than a days notice they'll plan they're daily meals accordingly.

It is on the early side but as you said, it is what it is...I am sure people would prefer that then having to go home for just an hour or two or killing time in between! Plus it leaves you all to have an early night. I wouldn't stress out about it, people will understand!

My rehearsal is at 1 PM and we are planning on having the dinner at 5:30. I figure people can go check in to their hotel and hang out for a bit, it may be nice to have some downtime!

I don't think I'd worry about it, tbh. I'm not really one to stick to a norm meal time though. Plus I never complain when someone is feeding me! Don't sweat it.

I would find 4 pm too early for dinner. You could do a lunch before the rehearsal leaving people a free evening before the wedding the next day, or you can schedule the dinner at a later time.