It could be binding. In fact, even oral / verbal leasing agreement may be binding in Texas. If you want to sure, ask the lawyer who is probating...

How many exits needed?

Likely not. Call the City Code Inspector and find out.

What does "the reletting charge is not a cancellation fee and does not release you from your obligation under this lease" mean?

Yes, you are potentially liable for future charges.

Can I break a door lock to find out occupancy?

Before you do so you'll first need to determine if there are any occupants in possession through leases or at least the consent of the previous...

Can a commercial landlord go after your home if you signed a personal guarantee

In Texas, your business and residential homesteads (with some limits likely not relevant here) are protected from creditors such as a commercial LL.

How many exits needed?

Probably not. But to be sure, you'll need to call the City of Montgomery Building Code Dept and ask, or research their Ordinances here:...

How can I get out of this lease?

Doubtful you can escape it unless (a) the Lease provides that no parties are bound absent your parents' signature; or (b) LL has not yet signed it....

I need help with paperwork for a loan from a family member and a property lien.

You'll want to coordinate this with a Collin County title agency who can order loan payoff statements and be sure that FIL has appropriate title...

Your letter must provide that you are terminating the Lease and state the date of vacancy which must be at least 30 or more days from the date of...

After he obtains the lender's written consent, a simple General or Special Warranty Deed is prepared making the transfer. Any real estate attorney...