I already do that last point, I usually make up some bullshit roleplay reasons why we are deploying to the colony and why I am doing my specific plan. (Ex - LV has reported CLF infiltrators growing and trading drugs, so we're gonna blow up their base of operations, the Hydroponics dome. Prison station has the political prisoner 'Lil Donny' who is Donald Trump IV's fifteenth son, we gotta rescue him, etc.)
It helps spice the round up and generally people seem to think that it's funny and enjoyable.
I'd be perfectly fine with forcing marines to deploy no earlier than 12:20 or 12:25 as long as all the tedious shit that they have to do gets removed, since none of the tedium adds to the roleplaying experience, and if staff claim that the early drops are a problem for xenos getting 'metarushed', xenos need to get fucking good and stop hiving in the same location on every map.