Small Scorpion:
Pincer vs Lera (1d20+7)[26] for (1d8)[4]

If it hits, grab then sting (1d20+2)[11] for (1d6)[5] piercing and poison
(1d20+9)[12] (1d4)[1] (1d6)[6]

If it misses, second pincer (1d20+3)[13] for (1d8)[6]
If that hits, grab.
If that misses a 3rd attempt (1d20-1)[4] for (1d8)[8] (because it's unthinkingly aggressive)

Then it's the big guy.

Khaza'dun is still grappled, so opening with a Constrict (1d20+8)[24] fort for (1d6+4)[6]

If Khaza'dun is still conscious it'll do it again (1d20+8)[12] fort for (1d6+4)[5]

If that still doesn't take him out, then number 3 (1d20+8)[24] fort for (1d6+4)[6]

Once Khaza'dun goes down it will join the attack on Lera (I randomly picked from those of you who'd damaged it).
So (1d20+11)[25] to hit for (1d8+6)[9] damage,
If successful and it has enough actions left it grabs
If unsuccessful and it has an action, it tries once more (1d20+7)[12] to hit for (1d8+6)[12] damage