Managing them is another world and there are all sorts of lovely aspects that newbies (who haven’t done research) won’t expect.

I only expected to make cosmetic repairs, redo the flooring, purchase a W&D (sellers going to purchase a new fridge & stove), then put a tenant in it.

This is the biggest challenge in long distance investing- I'd recommend you start interviewing again, and in your agreement with a new PM, very specifically line out what your communication and service expectations are so that there is no misunderstanding from the get go.  

You need to make sure you offer with a good amount of lease option money to the seller and be fair with your expectations or the minute they run a ridiculous scenario/ offer by their attorney or realtor, you're out like the fat kid in 5th grade dodge ball! 

Chase marketing and Chase legal don't communicate the way people would expect them to

Also management fee is based on expected gross income (EGI), which includes other income, not just rental income. so $27,700/554k =5.00%.

I would make sure to have clear expectations in writing for both you and your brother to reference during the course of the project. 

And the last one, which really depends on your market: Once you re-list the property do you expect that the previous exited contract will affect the future price you'll get for the property?

But before I do, what can I expect as far as monthly fees?

You can have only one showing, set the expectation for your seller not to be at the walk-through with the other potential buyers and they completely avoid that interaction.