Yes different languages.

Check the language of your offer.

Do you include any language in your lease that they must pay a certain share each month?

If zoning doesn't permit business leases, you can always have a real estate lawyer draft up a suitable NNN Residential Lease with Sublet Options... you just have to make sure it's worded plainly and with enough residential language to keep the city happy should they come knockin. :-)

Yes, with the original language, the lease renews each month for a month at a time until either of you give a written notice, although with the cross-outs, it is now unspecified when that written notice is effective. 

They speak your language.

Depends on the contract language.

There are usually a lot of attorneys and title companies involved in wholesaling....I don't think all those professionals would risk their credentials if what they were participating in was illegal.Like everyone said, look up your local laws as they are different in all 50 states but as long as you are following the language in the contract the seller has signed you should be fine.If it says don't market, don't market, if it says no assignment, don't assign...if that's the case, get a new contract.

Here in Orlando, that's what I'm currently trying to do but the contract clearly has language in it that shows it is meant to rent out a whole property. 

There may be ethical reasons to not assign a contract (my personal opinion is that (1) if the contract provides seller financing or other terms that rely on the performance of the buyer after the closing, it is unethical to switch buyers without the seller's permission or (2) if you haven't properly vetted the assignee or used language to prevent them from also assigning to someone who can't perform and you are not able to close if they fail to, that is not fair to the seller) but that is a personal opinion not a legal distinction.I'd be interested in taking assignment of your contract if it is a truly profitable deal.