In lower levels, maybe up to 12 or something like that, champs with AoE attack like Galek should be strong enough to kill all spiderlings, so you don't need a real strategy beside that. Maybe you have to fight manually, so that the Spiderlings aren't killed to early and respawn at the wrong time. Kill them right before the big spider get's a turn, so she doesn't heal.

Team: Spider (you should book him and level him up, great def debuff champ), Galek, Royal Guard, Samar, Achak (he can freeze all Spiderlings, so they don't attack you).

Of course this is not a team for Spider 20. You definetly have to level up some champs and get some more of them, you don't have a good healer at your account.

Should Spider be my lead? Thanks!

It depends on the aura you need, spider, royal guard galek and frozen banshee all have great auras. Keep in mind the accuracy you need to land debuffs for each stage is roughly 10xthe stage number. for stage 1 it's 10, 2 is 20 and so on until 20 it's 200 ( stays around 200-230 for all stages through to 25 ) 

I was thinking either FB, Spider (bc Skadi recommended), or Samar bc his Aura is 30% in all battles; twice as much as Galek.