@Jake Keating I’d suggest consulting with a local tax and/or estate planning professional for advice on this issue to make sure you get the best advice for your specific situation. 

These guys might be ready to downsize or move into a living situation with assistance.

I plan on renting out the home for several years and hoping that the IRS liens will drop off before I ever consider a sale.Does anyone here have experience in dealing with a situation like this?

(Don’t fight the hypothetical, that’s the situation)In trying to finance the flip, which will cost between $40-$50k, the only way I can think to finance it is a HELOC.  

They have something going on in their lives that is motivating them to unload the property as fast and with as little stress as possible.I'll give you an example of a seller I worked with that you can share with your wife to help her understand the kind of situations we regularly come across.This guy had his house up for sale by owner because no agent could help him.

It became clear she wanted to milk the situation whether she had any legal standing or not.Day 3: Send written notice of change of ownership and officially serve 60 day notice to vacate.

We once had to wait 4 months to close bc of a probate situation, due to notice of creditors that wasn't filed.

In that situation I would give her both and tell her that I would tear up the 30 day if she pays in 3 days. 

However, your situation is clear.

You've shown you are open to treating for rodents and you've taken reasonable steps to resolve the situation since they've only been noted outside the unit.