Again, effective or not, his only real criteria would have been that they STAY THE HELL OUT OF HIS WAY when it comes time to say "Hi" to E.T.
Not to beat the dead horse too much more, but that makes absolutely no sense. Weyland could not have been stupid enough to think that he only needed a crew barely capable of getting him to an alient planet, and that after that the crew was expendable and everything would go exactly as he wanted it to. The man hadn't a clue what he would find.
You are going to MEET AN ALIEN SPECIES YOU (SOMEHOW) THINK CREATED ALL OF MANKIND. This is not a job for amateurs.
Even if Weyland cared only for extending his own life, and absolutely nothing else, would he not surround himself with the absolute best that his massive amount of money could buy? The best. No ands, ifs or buts about it. Top shelf talent. Bright, razor sharp minds with extensive training and massive contracts (with clauses for a successful mission completion).
The way things went down he could have hired a pack of Cub Scouts and the results wouldn't have been much different.