Is new owner supposed to honor lease from previous owner in Illinois

Not a VAST difference, but not the same either. You should have a lawyer create an AirBNB or short term rental type agreement and you should not use a standard lease agreement. As examples, the short term agreement might cover check in and out policies, prohibit big parties, etc. and more.

We would want to review the restrictions in the lease to be sure of the answer to this question.

I suggest you consult with an attorney who handles commercial real estate transactions. I suggest you as what charges you will be responsible for - water, heat, electric; what alterations are allowed; what repairs will the landlord cover; if the landlord will abate rent for COVID shutdowns.

If your lease doesn't allow a sublease, you can't do it. I'd just approach the landlord and see what could be done. If the person moving in would be willing to sign a one-year lease and do the typical background check, the landlord may let you out of your lease.

I suppose it doesn't matter if you have the lease giving you permission and the lease is long enough to justify the building expense when you won't own it. But I'd buy the land so you could eventually sell the property with the building on it.