SP,
Welcome to the forum from another Michigan pond boss member. Tilapia are legal in michigan. I found a local hydroponics guy who was advertising to sell them on craigslist. He turned out to be close to me and was nice enough to deliver them.. He has checked on them over the course of the summer and would even be interested in finding a way to net them out for me and overwinter them in his indoor tanks and then loan them back to me for algae control next spring. It could be a good business, like the people who truck bee hives around to help those who need seasonal bee work.

Tilapia eat algae mostly. They do help with some natural aeration action by stirring up the debris on the bottom as they sort through it.

I don't know where in Michigan you are, but there is always the option of ordering fingerlings on Ebay. The problem with small tilapia is that big tilapia are expensive to ship and to keep alive, small tilapia ship fine, but then don't eat enough unless you buy scads of them. You need bigger tilapia to eat enough algae in the short season that they are alive in the summer. They die in the fall.

My bigger tilapia had young and now I have thousands of young tilapia all wishing there was some algae left in the pond to eat.... They will all go belly up very soon here.

I have to figure that some 'stirring' of the water whether it be with bottom aeration, surface aeration, or even just taking a trash pump with 3" output hose and just blast the bottom to stir everything up every week would help. taking a row boat with an outboard and stirring things up with propwash would help too.

If you could get the HOA to kick in some funds you either fill it in and save money and headaches for evermore, or you kick in funds, pump it down, dredge it to a depth where it could be more sustainable, then aerate.

I'm not an expert but the warm water, shallow water, no new fresh water coming in and perhaps years of sediment build up (did you say how old the ponds are) are a challenge.

Barley straw is a limited helper. Even if tilapia took out all the algae you may have other aquatic weeds to keep up with.

Pond dye could be considered if homeowners are Ok with a blue or black water color.