Electrical connections and other q's!

That's possibly so you can read the solar charging on the control panel, is it an EBL control box

It doesn't really matter where things are connected as long as the cables are appropriately sized and fused accordingly. When the loads are high you want equal length runs for your positive and negative but that is generally only for battery to battery and inverter connections. That said it generally makes sense to feed everything into a fuse box so you can manage it easier. If you look at my picture you'll see a positive and negative bus bar direct to the battery. These handle the heavy currents(B2B etc) and all the positive cables are appropriately fused. I then feed the 6 way fuse box from the bus bars to handle the smaller currents like the solar, 240V changer and general camper electrics(lights, water pump etc). That picture is not the finioshed job but hopefully gets the idea across. Good luck.