This is all very interesting and I think that I follow the basic concept in that if a panel is producing insufficient power, its bypass diode(s) will activate so that upstream power can be diverted around the low-performing cells. This is good to know.
It's not clear to me just how much of the array will encroach into the shade caused by the higher roof. I do know that the (4x3) array is 17 x 13.5 ft and that the garage itself is 24 ft wide. I'm guesstimating that the shade is at most 25% of the roof so my feeling is that most of the array should be unaffected by the roof.
My concern has been focused on what effect the tree will have. It sounds like it shouldn't have as much impact as I had feared, particularly if I am proactive in pruning.
Many thanks for the explanations!