That's is a tough one--small, native and deer resistant. This would make an excellent subject of an on-line search. But there are always exceptions to every rule. I am wondering about witch hazel. Have been thinking about it for my yard, there are new ornamental varieties out there. It is shrubby but I guess can be pruned into tree form. I wonder about ironwood too. I rarely see that tree for sale though. I saw sassafrass listed, but have never seen that tree for sale in a nursery. BTW, I have no experience with any of these trees in a deer intensive environment, so take these conjectures for what they are.

Was just out at a state park to day and saw many witch hazels. Asked the naturalist about their deer resistance, (this is in eastern PA, a place with a lot of deer damage). He said they are not a favorite but do get eaten. He also said that deer don't eat cherries. You might try a dwarf cherry or try to find choke cherry, which is black cherries smaller cousin.

You might try redbud and protect it until it gets enough size to fend for itself.

I'd try Amelanchier, dogwoods, hawthorns or crabapples - assuming you want an ornamental