No more texts...I'd visit the property personally and speak with her.For not renewing lease, I'm not sure where you live, but certified mail, a certain period of time before the the end date of the lease is necessary to terminate lease.You can always find the info on your state in the government records online, but if still in doubt, it may be worth contacting a local attorney. 

If he refuses to pay the towing fee, terminate his lease.

I live in that same area of the Lakes (Desert Inn and Fort Apache) and that is one of the best areas of Vegas so i don't see a reason why this should make a big issue for your sell.I would inform the tenants that an early termination can happen by the new landlord.  

Now when I notified my LTR tenant about terminating the lease (month-to-month) he expressed interest to buy it (i just sort of mentioned a market price range on phone).

If you decide to terminate and your agent tells the seller's agent, they often try to save the deal and fix the item, especially if it is something any buyer would terminate on. 

Last time I paid the handyman $85 to go troubleshoot it, and it turned out that popping the batteries out and in "reset" that connection to the Wifi bridge.

I always put an extension into the contract of 6-12 mos, but not everyone does, and they are perfectly within their rights to terminate the agreement at the end of the contract term.  

If there's another complaint, I would require them to remove the animal or face termination.

You may choose to terminate that periodic tenancy by giving proper notice to the tenant.