Oh gotcha, I would probably just take the cap off at the job site and drop it in.
You definitely could do that. I use 15 gallon carboys for downstreaming and they have two bungs, a standard size one and then a smaller vent one. I drill through the larger one and then just refill the tanks through the smaller one. It works well but my setup will be changing dramatically this off-season so we’ll see what I come up with
Again, I’m no expert personally, but my understanding was that any connection between the intake (bottom of the drop tube) and the pump (or even after the pump) was a potential for air infiltration into the system, which would decrease performance. The seal of the hose to the tank was more of what @DisplacedTexan was saying (to avoid sloshing, etc.), but the running of the hose all the way down without an elbow/bulkhead was taking several threaded connections out of the system.
