Might serve as a built in cushion should something come up, guest will know that you're trying and thinking about their overall experience.

I doubt many tenants would follow the watering schedule and do extra yard work.So, from a practical point of view I would go with the least expensive option but press the seller to give $11K repair credit for the most expensive one.This will provide enough safety cushion for possible plumbing repairs. 

Always have at least a 2% cushion when you borrow money vs your cash on cash return.

LOL - it's a little more than I'm used to handling all at once - I might have to raid the piggy bank and shake the couch cushions...

Add a significant cushion to your budget, and don't do eraser math to make your numbers work. 

I'll give them a little pop every now and then above what we agreed to just because I had some more cushion on a deal.Where I feel that helps me is when the numbers on a house are tight, I can beat them up on pricing a little bit and they understand its not me trying to stiff them out of money.

Once you have a three month cushion, keep adding to the reserve account until you have six months of expenses in the bank.  

You need some cushion for yourself and also for your investment property. 

Also, I would be planning to rent out the building, so would relying on cash flow be sufficient to cover that 5-10k surprise cushion?

The net income has funded 529s, which will also grow tax free, provided cushion for extra contributions to non-RE 401ks, which will also grow tax free, and has been funneled into index funds that will be held for quite a while, again growing tax free until sold.