The benefit is for investing capital gains into OZ's, not necessarily from selling assets that are in existing OZ's. So if you had a gain on your house (beyond the homeowner exclusion) you could potentially invest the remainder of that gain into an OZ project and get those benefits.

There are all sorts of stipulations you need to follow to qualify however - not all of which are fully in place yet from Treasury. We should be getting the first version of the regs as soon as tomorrow (imminent we've heard from folks in DC) and then we'll know more. Things like having to improve the basis of whatever you invest in by 100% within a 30 month period exist, so you can't just buy something in an OZ and park it, you have to actually do some improvement to what you purchase.

Not really, your own personal residence is exempt for capital gains (250k single, 500k married).

You have to make a 100% investment above your acquisition cost, so you probably cannot benefit unless you can sell it to an housing investor who could do that.

Rent it out while you wait for the area to improve. Or hold it and wait.

Or, if local zoning doesn't block it, see if you can rent it out as commercial.