Can you post a close up pic of one or two of those green patches. You may have a grass that will fill in over time with water and fertilizer. Don't put grass along that thin strip next to the house. Use a compact growing shrub, and fill in the bare ground with a nice wood chip mulch.

@Wil Haines, thanks for the heads up. I know the trend here now is going plantless and mainly rocks which is my last option (which I wouldn't mind aesthetically). I just wanted to challenge myself with the project

"I know the trend here now is going plantless and mainly rocks which is my last option."

The trend is not to go 'plantless'.....only to greatly reduce the need for supplemental irrigation by using water-wise or very xeric plants. And no lawn or turf grass - other than artificial ones - can be considered particularly drought tolerant.

Have you considered a drought tolerant but foot traffic friendly groundcover instead? Or artificial turf?

@Tom, here are some closer pictures of the patches of grass available...the wood chip mulch sounds like a good idea

Its Bermuda grass......its very drought tolerant, and spreads sideways to cover bare spots. Your bare spots are kinda big, so they won't fill in completely this fall and winter. Its too late to seed more Bermuda , but you can water and throw down some annual ryegrass to cover the bare spots for the winter. In July you can seed some more Bermuda , because the rye will die out in the heat. You have a fairly big leaf variety of Bermuda, so use something like 'Blackjack' Bermuda (available on-line) for a good match with what you have there. Looks like you need a 10 lb bag of ryegrass. (Home depot) Rake it into the bare spots at a depth of 1/4 inch. Water daily for the first week.......every other day the second week, and as needed after that- depending on how much rain falls.

I always have to ask where people live in SoCal. I grew up there and lived in many places from Hawthorne to Indio. Point is I know there are a lot of micro climates and soils to deal with, so it would help me to know where you live.

With common bermuda already growing as a volunteer, it's safe to say that bermuda would be a good choice. What you don't want is to get tricked into using the Marathon turf that so many people have. Marathon only works with daily watering in most of SoCal. With bermuda you can get by with monthly deep watering much of the year, depending on where you are. Another alternative is UC Verde buffalo grass. Both bermuda and buffalo need full sun, so any shade will result in very thin grass. You cannot seed or sod yourself to success with those grasses in the shade. UC Verde has a lot of benefits over bermuda. If you decide to challenge yourself with the UC, then I would kill off everything, twice, before sodding it in. That will prevent the immediate sprouting of weeds.

Now is NOT the time to be seeding bermuda. If you decide on bermuda and want something green for the winter, then "winter rye" will work. Then next June you can kill all that off, twice, and seed in the bermuda. Bermuda seed needs hot soil and you defs don't have that right now.

Another alternative is St Augustine. It needs water on about the same schedule as bermuda to stay green. One difference is if you stop watering for several months, it will die out. Bermuda will go dormant and not die out. But St Augustine will survive very well in the shade where the bermuda or UC will thin way out. St Augustine spreads easily, so a few pieces of sod, strategically placed, will give pretty good coverage in a year. It spreads about 15 feet per year in all directions. St Aug does not come as seed; only sod. It will grow anywhere in SoCal except in the total shade of the pines in the mountains. Clearly you don't live there.

For that hellish strip between the wall and the surrounding concrete (last pic in first post), how much sun does that get? It might be better for plants.

If you decide on a grass type, or a plan to get there, we can help with all the specifics you asked for. For now the answer depends on the grass type (bermuda, rye-bermuda, UC Verde, or St Augustine).