Leader: Zzaap guns are Orkish weapons, yes, but they are so freaking big not even an Ork can carry them so they need to be either Gretchin-propelled artillery or mounted on a vehicle or Monstrous Creature like the Squiggoth.
Tasunke: If you want Guardsmen with all the weapons they can carry, play the FoK mod for some awesome IG action as they get mortar teams, heavy bolter teams, and missile launcher teams as leader options for their Guardsmen squads, and the heavy bolters can be upgrade to autocannons and the missile launchers upgraded to lascannons. Also, you can upgrade your Guardsman squads with either a plasma gun, flamer, melta gun, grenade launcher, or sniper rifle. Since it is a closer-to-codex mod, your Guardsmen will die in massive quantities, but that's not an issue since you'll outnumber anyone but Orks 3:1 or worse.
Frankenfurter: Soulstorm takes so long to load and takes so much RAM since Iron Lore left all the textures they made in uncompressed TGA format.