I've stayed there a number of times and enjoy it a lot. I've never had a mini-bar in my rooms (I have stayed in at least 5 different rooms) and I don't think I remember having a fridge in my last 2 single rooms overlooking the garden area. I can't remember before then, lol!
There IS a nice breakfast room but I don't know if they encourage people to gather in there. I've not ever seen anyone in there outside of breakfast hours. I wonder if they go ahead and do their set up for the next AM as breakfast ends? I'd ask them via email or via phone call if this is going to be OK. I'd not just assume this would be welcome.
The "lobby" is little more than a foyer. There is a small step down area going out to the garden area Andi mentions which maybe has a small desk with computer and a built in bookshelf and maybe a small love seat but not enough room to sit with others. This is where the luggage closet is if you leave your bags before or after check out.
The garden area is very nice and you can bring in food and beverages. There are rooms that face onto this area so you'd want to be reasonable about chatter later in the evening.
I've had a variety of rooms there, none particularly good-sized. The single rooms are small and typical of rooms in large cities in Europe. The bathrooms are generally small.
The building is a listed building built in 1790, I think, thus the small rooms and weird little doglegs. I think it has a ton of charm and I like the neighborhood. My rooms on the garden side have had more light than the front facing rooms.
To me, it's going to be hard to find a boutique hotel with lots of common space as they need to make every square foot count for rental space.