Good post, except you're missing one ability which is actually THE very best: magic reflect. OWSTER ROTWELL is your best summoner choice here, like crowling against melee this one punishes all magic monsters hard.

There's a bunch of other monsters that have it and unless the ruleset dictates different most magic monsters just attack the front spot, so keeping your tank with magic reflect alive will easily obliterate the magic opposition.

With the target practice ruleset just put your magic reflect monster in the second spot (or first one behind any melee monsters upfront) and that should also easily take care of it, bit harder to keep alive though unless you have triage on your team as well.