I HIGHLY doubt that the leaks are due to overfilling it, unless its got an extra 5gal in there!
Their are many places for a leak to form at the front of the engine, so your going to have to narrow it down. It could be coming from between the gearcase and block, the geracase cover or the front crank seal.
As for a leak at the inj pump, not too many places for a leak there, just the oil feed line (between the pump and engine) and the o-ring that seals the pump to the case. It 'could' be leaking from the gov housing gasket or one of the plugs on the pump, but thats not very likely.
Leaks from the vac pump arent uncommon...
2007 Laramie 3500, Just breakin in the new engine with a few trinkets
2004.5 3500 600 series 2wd 6spd bone stock, my little rice burner
1997 SLT 2500, 5.5" fabtech, 36x13.5 IROKs, 5x12s, s300, 4kgsk