Describe what you are calling a firePLACE.

There are all kinds of ways to make paving attractive, beyond what plain concrete would be. Suit yourself, but the grass strips in between blocks of paving seem like a PITA to me, increasing the level of maintenance and limiting the placement of furniture.

Rather than a perspective view, do you have a PLAN view and pictures of the yard? If you need to take pictures, show complete scenes from end to end. Usually most easily done by taking slightly overlapping pictures and posting them individually.

Strips of an alternate paving material would be far more practical and easily maintained than skinny strips of plants.

By rectangular fireplace, do you mean one of the lower profile, long and narrow gas fired flame containers? Perhaps add some photos of what you are considering since I don’t see any ideas in your idea book.

How will you trim the grass and keep it out of the pool? How much grass will get tracked into the pool by wet feet? Honestly, some designs are just visual treats, but everyday living problems.

Real grass in a desert is really not pratical and neither are the grass strips between pavers around a pool unless you don’t mind all the grass in the pool. We would need to know the size of your space to even begin to answer. An actual to scale drawing of the space with the pool marked in will be the first step.

I assume you’ll be installing artificial turf since it appears ( from the landscaping depicted ) you’re in an arid zone. That’s commonly done in the desert where my 2d home is, that’s what I have. My only comment is that I prefer an elevated spa for the waterfall effect. I would hire a landscape designer or architect to assist.