It's been a while so here's an update: I The flagstone has been moved to a path in the front yard that I will be working on installing correctly for probably weeks while temperatures are high. I planted some Euonymus plants which are evergreen and broadleaved to contrast with the juniper.
I also noticed a rhythmic humming/whirring noise from the pumps and the large rocks sitting in the intake bay were actually sitting on the pump vault lid so my son and I pulled all the rock out, removed the milk crates that were in there, moved the vault forward, refilled the intake bay with graduated rock sizes around the pump vault, and tried to reinstall things. The edging looks worse - the liner may have to be seamed but as long as I keep the water level where it's supposed to be and don't forget about the hose when filling, I should be fine. I'll have to fold and tuck the liner better when it cools off in a few weeks. It's just so hot.
Also, after putting everything back together, the pump for the bog stopped. I unhooked it and pulled it out, took it apart as best I could and actually broke the impeller trying to get it out to fix whatever had stopped it. So now the waterfall pump has been switched to be the bog pump while I wait for a new (different brand) of pump to come in the mail.
The hair algae is finally taking off. Probably has something to do with the approximate 50% water change I had to do while working on the intake bay. I know it'll level off and die back as the plants take hold, but I'm wondering if I should get more than just the 5 fish that I have to help keep the algae in line.
I'm also telling myself that the leak from when my glue job went wrong connecting the flex PVC to the rigid PVC at the bog isn't a big deal and the bog still works. I'm torn beween "I really don't want to take everything apart, the water is staying in the system fine, and the bog seems to work okay" and "What if ice forces the opening larger and things break this winter? Maybe better flow into the bog could help the waterfall out of it be better too...". I calculated total dynamic head at a little less than 5 feet, so the pump should be kicking 4000 gph into the bog, so I'm already a little on the fast side, in theory.
But on the good side of things, I got my first blooms in the pond! Yay!!!
I also started adding more 1" minus rock to the bog to cut down on algae and give me more room for shallow planting. I can always kick the rocks out of the way to plant something deep if I want. Not sure I love the dry rock look though. I like seeing the wet rocks better.