@Kahless do you have any experience with hackberry? This is my first one so would love some ideas/ tips
I've got one I collected this year and have worked with them, particularly the southern variety (celtis longaeva). They are pretty much bullet proof, like an elm. I dug mine up with no feeder roots, plunked it in a bonsai pot with bonsai soil and it sprouted new growth in a week and a half.
I had a tiny mame sized one I got from Guy Guidry a decade ago. It's leaves were reduced to less than a 1/4 inch with dense twigging. It was also a southern hackberry and was a bit sensitive to deep cold. It lost a bit of ramification every winter. I suspect it did that because it was a small tree and the temp swings took a toll.
You have the Northern variety (celtis occidentalis). It is a tough customer. Probably more winter hardy.
As far as care, full sun up your way. Regular bonsai soil. Prune in late winter to push ramification. Fertilize regular fert every two weeks.
This one that belongs to some friend is occidentalis. The tree was in an exhibit in Richmond in Feb. It was collected in central Va. cowpasture 35 years ago. Note the intense ramification that's possible.