Make it as comfy as you like lol. Hopefully no one will be trying to move in 

You got everything covered I think, good shower etc.

Decent clean bathroom.
Vantage point where you can look out of the window and see them parked.
If a block of flats, intercom entry, so you don't have to run downstairs in your whore clothes. If a converted house, for preference a separate entrance.
If possible your front door should open onto the hallway so you can keep your lounge/kitchen door shut and just keep clients within your bedroom and the bathroom (so ensuite is useful. But if you're not living there then this isn't such a big deal as far as I'm concerned.)

Washing machine/dryer.
Just think of it like this. You are at home and you want to fuck your bloke. What would you have around for the interior, and how would you tie him up to the bed and answer the door if you were expecting a parcel without given the postie an eyeful. And that from time to time you are going to have to eat and drink etc. Then look at where you are going to keep all the towels and extra bedding cos realistically you are going to need more than one set of bedding. Bathroom layout could you and a client both get in the shower and actually check the pressure of the shower. Flush the toilet, as well as some buildings, have horrific noisy piping.

Then look at how you are going to let them in and out of the place. If a converted house how the soundproofing is.
How secure is the building for when you aren't there.
 
Nosy neighbours, unfortunately until you are living there you aren't going to know. Mine seem really nosy, however, they really aren't and I could realistically work from home. Although do check to make sure its not a neighbourhood watch area.

Parking it's not the end of the world if you haven't got street parking, in fact, it could be better if you didn't to minimise noise. There's a fab app called GoPark. I use this all the time to find free/cheap parking.

I'd actually make an argument for carpeting, as it doesn't half help with soundproofing with the floor below if you're first floor or above.

A decent-sized bedroom that has a wall where the bedhead can go that isn't a wall between you and a neighbour.

Nice bathroom, or at least clean, presentable and with a decent shower.

Agree in a flat a tumble drier is useful (plus towels are softer).

Buy plenty of bedding, especially throws/thin bedspreads and towels. A clock, candles or soft/fairy lights, maybe something to play music on, somewhere to store condoms, and a discreet bin.

Lots of things covered above but (and I don't think I missed it) as winter is approaching, a decent heating system or at least one in the bedroom. I know some escorts using flats for just the odd day or few hours don't want extra cost for heating a room but I have read several comments from men saying the room was freezing!