We could meet at the foyer, at the shop, at the cafe, at the room with the portraits of kings or at the gallery with still livesstill life gallery. We could meet at the foyer, at the shop, at the cafe, at the room with the portraits of kings or at the still life gallery.

"at" works for all of these, but suggests that you may be thinking of meeting *outside* these areas. If you want to meet "at the foyer", I might expect to find you standing at the front door, just outside the foyer. You could step through the door and be in the foyer, but you haven't - so you are only at the foyer. Same for all the others. Maybe you're in the shop, in the cafe, but maybe you're standing just outside the entrance. "In" would explicitly mean that you want to meet inside these rooms. So if I meet someone while looking at fruit for sale inside a shop, then I "met them at the shop" or "met them in the shop". But if I meet someone just as I am about to walk into the shop, but without actually stepping through the door, I didn't "meet them in the shop". "Gallery with still lives" works but sounds a bit awkward.

Now that we've watchedseen all of the paintings, sculptures and installations, where could we meet with Chris? Now that we've seen all of the paintings, sculptures and installations, where could we meet with Chris?

It's strange to watch a painting. You watch something when it's changing or you expect that it might change. So you watch TV, because it's changing. You watch people, because they're moving around. But you would probably only watch a painting if you were a security guard and you wanted to make sure people don't steal it.

B. I'm thinking of the gallery that has those abstract paintings in the rainbow of colours. B. I'm thinking of the gallery that has those abstract paintings in the rainbow of colours.

Not wrong, but not very natural. Maybe "those abstract paintings in all the colours of the rainbow."

He's so much into modern arts. He's so much into modern arts.

I can't decide if this is natural. Something like "You know, because he's so into modern art" definitely would be.

frankly I'd rather meet with him in the Van Gogh gallery, in front of the breathtaking sunflowers. frankly I'd rather meet him in the Van Gogh gallery, in front of the breathtaking sunflowers.

I assume the sunflowers are Van Gogh's famous paintings; a comma is necessary to say that. Otherwise it sounds like the *gallery* is in front of the sunflowers. "meet with" is not wrong but it's a little unnatural here, we'd probably just be meeting him.