I do not believe the negative cash flow will be a problem, as I should have around 6-10 months of cash reserves! 

A lease option on the other hand consists of two separate agreements, a lease (no problem), and an option to purchase at some point in the future (no problem). A

So that's not nearly as much of a problem as finding a way to lock up the new property but not let him take title to it before he completes the sale of his old property. 

lol  Anyway, I'm glad you don't think being too nice is a problem.  A

No recommendation as I'm in SC, but I run into that problem as I buy sub100 and even sub30 as well, but have found small credit unions usually are the best place to start.

Financing is not a problem as I have decent HELOC on my primary home.

An old man that I know well who was living a block away from where I've purchased my first property had a heart problem a year ago and was forced to move 3 hours north in an assisted living community to be close to his daughter. 

A good Expediter may be able to solve this problem as well.So, before you go to the Architect, I would first do some leg work and find out everything correctly.OR, you can just hire an Architect.

“The failure of a landlord to provide such conditions can lead to violation of the law and impose civil and, at times, even criminal liability upon the landlord”.Please read up on your local laws as relates to landlord obligations for habitable premises.This to me is a no brainer and am sorry am not trying to be mean to you.You inform tenant of your duty which his really to their advantage and then you go in and address.If tenants want to prevent you from treating, then suggest that they provide you with suggestions for pet friendly/kid friendly pest control to use and suggest that you will attempt that for a short period of time to see if it works but in the end, if it does not you will need to come in with a different approach, different product to address the situation.If said tenant continues to fight you on the issue, I suggest moving to contacting an attorney about providing a notice to comply or quit possession.You are running a business here.The unaddressed rodent activity is only going to get worse because you have a tenant that is difficult.Document your approach to resolve and try to have them chime in with their own suggestions on the agreement that if it does not work you will have no choice but to use an alternative.I would then start working on rethinking that lease term as that there sounds like a tenant that will bring you trouble.You have a legal duty and if a tenant is keeping you from completing it, that there is a problem as the same tenant will turn around and make false allegations and/or accuse you of not addressing the issue when all along you have been trying to do just that.Be the boss here, it is your property.This is like a grown kid that wants to test your limits, I suggest you put an end to that nonsense as life is too short and you have too much else to do than allow your time to be wasted by stubborn tenants.Side note:Glue traps – so cruel and gross.Peppermint has worked well for me too as @Marci Stein suggests. 

I would bid it at the steps no problem as I have been doing that for decades.. but talking them into signing it over with that massive of equity..