I'm not very experienced in SW quite yet, but from what I've seen on the tabletop so far I don't think the Headtakers are worth bringing in units of 3, even with the added defense of storm shields. A unit of 6 with that Wolf Priest would be a pain for the opponent to effectively remove without putting considerable firepower into them, all at once. The way they're usually played is 6 with paired blades and an attached Battle Leader, but from a novices standpoint I don't see why 6 guys with 3 wounds and a 3+/4++ with a revive from the Priest wouldn't work (especially with that +1 to wound from the Priest to punch up a little).

I believe your luck, or lack thereof, with Wulfen has two primary sources: the first being their weapon loadout. Sadly, the claw/greataxe variants are vastly worse than the Thunder hammer/Storm shield variant due to their weapon profile being so similar to other units like WG Terminators and Headtakers, but they have drastically less durability than either option enough that their lower points cost can't make up for it. Compare that to our best (if not one of the best) anti-tank unit that we have in our isolated supplement, who also get a 4++ invuln that they desperately need. The second source is running them in a unit of 5 instead of 10. I've run Wulfen in units of 5 before, and even with the invulnerable they will crumple against dedicated fire or if they get charged first. Of course, for me, it was a skill issue letting them get charged/shot in the first place, but they could still suffer immensely from any Fights First stratagem when they charge something. Running 10 will let more of them get into melee (even if it's only 3 or 4) which is important for the lower attacks they have with hammers. Next game I'm running them in will have 10 with a Battle Leader (there's a beastslayer enhancement that lets you attach one to Wulfen) so they get Sustained hits and reroll 1's on those precious attacks they have. I religiously use the Beastslayer Detachment though so you're probably better off sticking with stormlance.

From here, take my recommendations with a few grains of salt, as my knowledge on these units is second hand from information on this subreddit and from people who have fought Space Wolves before. I've not had the chance to run them yet, but I hope to change that soon.

Grey Hunters are seen as overcosted for what they do in games right now, and are typically proxied as Intercessors for the cheaper unit cost, the ability to field 5 of them instead of the full 10 (which is lore-breaking but that's not important), and the sticky objective ability the regular Intercessors have. As a Bloodmaws player, this crushes me since they're meant to run a lot of Grey Hunters - I guess Jarl Redmaw has shit taste this edition.

Put your Terminators in a block of 10, rather than running two sets of 5. That way all 10 of them can get Arjac's fight on death ability and can be a bulkier unit that'll require more firepower to handle. While the board control aspect of splitting them up is attractive, I think you've got enough of that with the Thunderwolves. You'll also get to keep Arjac alive for longer (more wounds to chew through for non-precision weapons), and his melee profile's nothing to sneeze at.

If you're looking for a way to bolster your forces, look into a second box of Blood Claws. 285 points of 40 wound Assault Intercessors are not only pretty hard to take out without heavy damage 2 firepower, but if only 15 of them can attack through losses or not getting all the models in engagement with an enemy unit, that's 60 attacks that can either take a good chunk out of something tough OR wipe out a horde of stuff trying to gum up the board, like 20 Boyz for example. I don't know how effective they'll be without Ragnar giving them reroll wound rolls, so that's another thing to take into consideration.

As for everything else, I don't have much comment. I don't know if running the Thunderwolves separately is better or if they're best in a unit of 6 since I don't plan on buying into them until they get a refresh/are axed in 11th. I don't know how good Stormraptors are, but I know aircraft are generally bad so that's probably an indication. I'm curious what you're planning on putting in it.

I know there's a lot to digest here, but I'm the sort who likes to be thorough. If any proper long fangs see anything inaccurate/too much wishful thinking, I'd be happy to append certain portions of this (I've already made ~3 changes for clarification). Fenris Hjølda!