I was thinking of that as well, but decided against it. Dawnbringer is not only for protection from skull, it’s also from spells as well, for all your troops, which is something Sylvanimora can’t give.
That’s why it’s better to just use Archer-Dawnbringer with Entangle-first-turn talent. It will give you enough time to get Maw going, and after that, skulls is not a problem anymore, but enemies’s spell can still be troublesome, even with Dawnbringer’s protection.
This team is pretty tight, as losing one troop can be your doom. Game will be much slower without Maw or Wrath, but without Alchemist or Dawnbringer, you almost have no chance to recover.
Although, I recommend skipping 250 and go straight to 300. They’re both as hard, but possible with some luck, and you shouldn’t waste your luck on 250.
TheIdleOne’s team suggestion is also great, you just don’t get to use Xerodar’s Deathmark-first-troop-when-damaged as often, but it’s more safe that way. Good luck!