My lease doesn't allow subleasing unless there is written consent.

The commitment letter had the following language;Transfers/Assumability: Subject to Lender’s then-current underwriting requirements and compliance with the other requirements of the loan documents, the Loan is assumable by a qualified transferee of the Property for a fee of 1.00000%of the unpaid principal balance of the Loan at the time of such a transfer (a “Consented Transfer”).My question relates to the terms of the loan and savings to the buyer.

Land contracts usually have wording included in them that specify that the seller will be in breach of contract if they further encumber the property without the written consent of the buyer.

The Tenants agree not to permit any deterioration or destruction to occur while they are occupying the property. 19.ALTERATIONS:Tenant shall make no alterations, decorations, additions, or improvements in or to the premises without Landlords’ prior written consent, and then only by contractors or mechanics, or other approved by Landlord.

It's normally illegal for the Landlord to change the terms of the lease without your written consent.

They could very well lose in which case they will no longer be allowed to host properties without the property owner's consent.

You would also layout whether each of you would require the consent of the other to sell your share to a third party {or whether that would be permitted at all}; whether each party has first rights if the other decided to sell; and the terms under which one "partner" could sell to the other.  

Without my knowledge and consent, the tenant brought in a pit bull (or similar breed).

If she continued to make changes without my prior written consent, then I would again serve her proper legal notices each time. 

It says plainly in the lease no painting without written consent.