You’ll need an allen key to nip up the pinch bolts on the NDS crank too. Actually, “nip up” is possibly misleading – from memory, they’re supposed to be 12Nm to 15Nm or so which is surprisingly tight. The plastic cap thing that screws through the NDS crank and appears to fix the crank to the axle is only supposed to take up the slack so you don’t get side loading on the BB bearings – it’s the pinch bolts that actually hold the crank onto the axle (which is why they need to be done up nice and tight).
Dropper routing – your BB should have come with a plastic tube that fits between the BB cups so the rotating axle shouldn’t chew through the cable if you route it via the BB shell. However, you’d probably need to make a pretty tight turn to go that way which isn’t ideal…