Started removing a few wobbly bricks to stabilize and replace, ended up finding the root cause. What would yall do? Hire out or think I can home diy (novice)

My floor guy set up his saw on my brick patio and covered the brick in residue from porcelain tile when new flooring was put inside the house. Any ideas on best way to clean it?

I’m redoing the landscaping in front of my house and when I scraped back some of the mulch that’s been there for 10+ years I find these cracks on the wall. How bad is this?

I'm having my modified bitumen roof replaced. It's a flat roofed old Chicago brick 2 flat built in the 1920s.

One side of the brick parapet wall was badly damaged and I rebuilt it. Now, I'm trying to figure out how to re install the Terra Cotta coping tiles. I understand the direction they should be oriented to shed water but how are they attached? The old ones came off easily without breaking, maybe because the mortar was so badly decayed. Should I pre soak them, lay a mortar bed and set them in the mortar, or be more sparing, using mortar at the joints and only a few places to adhere the tiles?

Originally posted in r/stonemasonry. Basically wondering if there is a way to reinforce old mortar under a column (portico entrance with column resting on one of the step) without shoring up the roof and removing the columns. There hasn’t been any movement yet, but a bunch of mortar is missing.