Personally, I think you're on the right track, exploring how best to utilize solar for heating your pool and powering your house. I did both and they both have been great investments. My PV solar is just about done paying for itself, and my electricity is all but free for the whole year. My pool heater gives me an extra 5-10 degrees, which in some parts of the year is the difference between getting in or not, and that extra bump is always appreciated even in the middle of summer. Initial costs aside, running my house and heating my pool don't cost a thing.
I've never heard of a combo panel. That would be a question for a solar installer. But considering the systems together is something I would highly recommend. My solar guys install both systems, and so they were able to advise how best to integrate the two systems. They plotted out what roof sections to use for what. And they did the calculations for number of panels, and how the two system could work together, based on the local climate.
At the time, they sold a solar heater kit, which consisted of every single component I would need to install the pool heater myself, down to the pipe glue and even some rags! It was quite a bargain, I got my system in for about $3K. It would have been more than double that had they installed it. They sold me Helicol panels, which I still believe are the best. Not so much for the heat they provide, but rather for their engineering.
I doubt any well-known brand of solar panel is going to heat your pool any better than another. It's all just black stuff on your roof, after all. The difference in price has more to do with quality of materials, they way the go together and the warranty you get. The plumbing fittings are important, as is the mounting system. Those determine how easy the panels go up, and how long they'll last without maintenance, and how well they'll withstand the relatively harsh environment of a roof top, especially wind loads. So those are some things to consider in a buying decision.
And while I don't know of any combo panel, PV will play a part in your pool heating. It is the PV panels that will provide the power for your pool pump, which runs the water to the roof. That will all be calculated by your contractor, to make the electricity needed for that at no cost to you. You'll be running your pool pump more, and at higher RPM, to accommodate the solar heater, so that will be part of determining how many PV panels you'll need. I had installed my heater at least a year before I had my PV done, so I had a year of data (electrical usage of the pool gear) that was used to design my PV system. They got it dead on, I come out about even at the end of the year (power used vs power generated), which is what you want.
Another consideration my contractor offered was the installation of a heat pump, rather than (or in addition to) my solar heating panels. This, too, would require additional PV panels to get a net zero electricity cost. But I didn't want to buy or maintain a heat pump so, for now, I'm just using solar heat. But that is an option going forward, as I have additional space for PV panels on the roof.
We may have electric cars shoved down are throats in the not-too-distant future, so that is another set of additional panels to consider. All things you would discuss and plan with the right contractor, who should be working with you for both your immediate and future needs.
I would recommend contacting as many local solar contractors as you can muster. Have them each come to your house to give you a quote. Discuss with each all the various options, and see how they perform. You'll likely get their "slick" sales guys. You'll have to wade through their come-ons vs the actual data, but by the end of that process you'll have lots of quotes, all with charts and diagrams that will help you with your decisions. Then look up the reviews on the installers and see how others have faired with them. I wouldn't recommend the big internet guys, they end up hiring the same local guys for installation, and take a cut. I don't like the sound of that. You want a local company that has been in business for years that knows the area and local climate and can provide the service you'll need when you need it.
The process takes a while, as do the installations (getting on their schedule) as does the final startup (PG&E gets involved and slows the process). So if you want to be up and running by Spring 2024, you'd better get moving.
