To get 3 different inputs going into my batteries at once was going to cost lots, add lots of complexity and weigh a few kilos. It surprised me how much. But I do have lithium so they add a lot of palava as well, put all 4 together and Na, not wiling to go that way. As it is I have huge fuses and some other serious looking sh*t due to the lithium.
So I can solar or mains/generator but not at the same time. Might be able to solar and outboard at the some time, just tuning that right now. The OB puts out a huge 80W so not like it anything serious.
And I'd say clear of panels with built in controllers for 2 reasons, one being exactly what Chloe said and with combo units like that if one bit craps out you lose all bits......maybe forever.
A good solar controller to take a few hundy W is cheap. Mine can handle 400W input, is tweakable to tune for assorted inputs and output for what battery type and for heat. Cost 280 I think it was.