Nope, they can't leech life or mana for you.  However, auras granted
by equipment or from your merc will affect your skellies.  As an
example, a popular merc for skellimancers is the Nightmare Offense
merc from Act II.  This is due to his Might aura which increases his
damage and the damage of all your minions within its range.

See Frank's response.

One other thing though: when skellies kill something, they do that using
your MF.

Beyond that, most skelliemancers look for +skills gear. The more the
better, while of course not forgetting their own resists.

Regards,

Patrick.