The thermal solar panel should be moved next to the solar panel, and the basic heat exchanger and pipe next to the vanilla ones.

That's a matter of opinion. The thermal solar panels are not exactly analogous to the solar panels, and an attempt to sort the buildings differently may not play nicely with other mods anyway. I also don't particularly think of the buildings as "tiers" of existing ones, but rather as components needed for the solar thermal complex, so I prefer to just have them grouped together.

I could maybe create an option for different ordering the next time I update my mod, but it will depend on what I have the time and energy for.