Well, prepare to be disappointed. They somehow managed to make not one, but two bad lores.
Slann one
1) Healing from GHB, but d3 if rolled 10+ on cast;
2) Gives fly to target from GHB;
3) D3 MW and remove artefact from GHB, but easier to cast;
4) +1 for casts to allied casters (not the caster himself);
5) MW on 5+ for each model in targeted unit;
6) AoE dispel endless spells.
Considering that you can shift spell for slann in the end of the phase, the lore is okayish at best. Tempest is nice horde cleaner and Unforging is way easier to cast, considering all possible bonuses. Healing is meh, and fly can be shared through CP. +1 to casts can be useful for ultimate kroaknado.
Skink one:
1) Auto-pass battleshock for 1 unit. On 10+ cast roll it is AoE;
2) Reroll 1's to hit from GHB;
3) Ignore negative effects of terrain piece (worst spell in the game, IMO);
4) Chose a unit and roll d6 in the end of each phase. On 6 it is d3 mortal wounds;
5) Bind an endless spell;
6) Exactly the same as Tempest, but 12".
First is useful for Coalesced armies, second is good since we lost out universal rerolls and the last is good if you know you are facing hordes.
Very disappointing lore. It feels very unnecessary and not a strong power multiplier. And slann cannot use skinks spells. Absurd fluff-wise.