Why not try
Anodized Robo Cub breed 7 (H/P)?
It has
Supercharge that will buff next attack by 125% in 5.2, and it has
Demolish which will hit for 1390 Supercharged and 618 for second time. 1998 dmg in total.
Or
Lil' Deathwing (if you have an access to it):
Roll hits for 189,
Cataclysm hits for 1272 and then
Tail Sweep hits for 707.
2168 dmg dealt.
Or
Stunted Yeti (only H/B available):
Haymaker hits for 733, you can use it 3 times for 2199 damage.
Or
Clock'em (if you are in Brawler´s guild)
Haymaker hits for 693, you can use it 3 times for 2079 damage. Clock´em is much faster than Stunted Yeti, though
Also
Yellow Moth (P/P) would be nice:
Moth Balls (assuming 4 hit and 1 crits) deals 996 dmg (181 per hit),
Moth Dust hits for 542 and then Moth Balls hit for another 996 . That deals up to 2534 damage and almost always will attack first.
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Your
Ashstone Coree could only do 1260 + 280 = 1540 by
Crystal Overloaded
Instability and then 280 with
Burn/
Feedback and is not fast enough to have *guaranteed* turn advantage.
And while
Imperial Silkworm may have some heals, it is too weak and will dish out only up to 1540 dmg, assuming it goes Moth Balls - Moth Dust - Moth Balls and 8 balls hit.
On the other hand its advantage of being critter is not that only few used abilities are beast type but in fact that it takes less damage from elemental abilities, which are very, very widely used.
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Anyway, this seems to be a legit strategy, at least on paper

Good job