Being under the weather, I just connected all of your threads.
You may already being doing this, but since there are multiple threads I wanted to mention this.
You appear to be dealing with a water management issue ... two really. And it should be treated as two whole problems, roof and yard drainage, rather than in a potentially fragmented/piecemeal (which is the impression, right or wrong, I get seeing posts with a narrow focus).
I would start with the roof and gutters as that may address some issues such as around windows (if water is getting in) or the yard (depending on where it is discharged) and then the yard.
Regarding the yard there is a fellow over on youtube that has been referred to here, I believe the channel is fenech drain man. It might be worth you checking out for yard drainage, he has one episode where in a flat yard he slopes the drain pipes and uses a lift station to move water into a leach field. Perhaps that could be adopted to address your yard without having to regrade and remove/replace concrete.
It sounds like you have mostly abandoned the irrigation system, but if you are using it consider deactivating it. I live in basement territory and I've seen a number of wet basement that magically dried up when a nearby leaking sprinkler system or water main was repaired/replaced.
Thanks! Yes, we are dealing with water issues. There are actually 3: 1) roofing and or gutters 2) windows 3) yard drainage.
The issue with the windows we're kind of just 'surveying' at the moment. I bought a bunch of polyurethane caulk and sealed around all but one window (on the second floor) that we could access. I'm not confident this will resolve the issues we're seeing but I figure it's worth a try. If not, then we'll eventually just need to have the windows removed, framing redone and waterproofed, and new windows installed but that'll be later down the road.
Right now we are trying to solidify the roofing/gutter situation. First step is to get the gutters removed before we can really see if there are issues with the roof. Our roofer didn't show too much concern but we won't know until the gutters are off. What we do know is the siding needs to be re-done behind/under certain parts of the gutters and for this we need to bring in our stucco contractor to waterproof and patch up the problem areas. We won't know the extent of this either until the gutters are removed. So that's really the first step.
I have seen the French drain man as well as another guy: Apple drains. Both seem informative. I'll have to consider different ideas for this side of the home but am thinking some combination of french drain, dry river bed, and standard PVC piping tied together may be in order here.
Regarding irrigation, I'm on the fence about it - I think what I may just do is cut the existing line (which branches into multiple parts of this area against the home but eventually feeds the backyard) and replace with a single clean line or two for the backyard extension. I would probably remove just cut out and remove the manifold too. But whether or not we leverage the existing lines and or add to them OR we abandon the system complete, we'll want to decide that prior to filling in this area so that we don't have to dig and lay another line later down the road. We really need to do some form of landscape/irrigation design and think about zones and where we may want to plant things.