The space is 6.5 feet by 16 feet. I need some ideas about how to make the
area look nice. How many roses can I put in that area? Should I use
decorative rock? Should I make a path through the middle, so I can walk
through and prune roses? Should I kill the grass with chemicals, or remove
them without chemicals?
What would YOU do if it was your project?

First of I wouldn't use chemicals to 'kill' the grass.
Easiest way is to get a plastic sheet and cover it for
3-4 weeks which will 'cook' it.

Next I'd make the area near the wall into a 3' deep
raised bed to about 24'. this will make it oh so easier
to clean and prune. Also the level changes will allow
you to fill the fore& back ground with color.

The bench idea by tom is pretty good.
Bird feeders there though will attract cats to
the top of wall from where they might attempt
flying leaps @ the birds.

Its pretty obvious that if you put in roses they
will be fairly close to you. So try putting scented
varieties. And wait for them to surprise you. Thorny
giants should be a no-no.

If you can put a Felicia in there. My scented in
the heat and sun favorite. For some reason
cool weather reduces Felicias scent.

--
Theo in Zone 5
Kansas City