I am not sure its risky to speak with them or involve them in the IS . . . but Alaric is grabbing for all the troops he can, and while the Wolves might not have been as close to them as the Coyotes, the Scorpions feel they have a obligation.
I still do not think we will see non-wolf entities brought in to assist. I will go so far as to predict that we will not even see what remains of the Kell Hounds courted (although, it's obvious who they'll go after, you do not even need to elicit their assistance to get them going after the Falcons) because if you bring in an entity without origin ties to the Wolf Clan, it opens the door to attacks on the strength and legitimacy of the Wolf's claim on ilclanship. The assistance brought in would have to be strong enough to doom anyone who would even question the Wolf claim.
The main exception to the above, as far as I can see it, is absorbtion. If they can find groups willing to be absorbed into Clan Wolf (and thereby become wolves) then that's just growing the Clan, that's not exterior assitance.
Beyond even all that though, I do not think the scorpions, as we last saw them, are in any position to render Clan Wolf assistance. In the Wars of Reaving, they were run out of the homeworlds on a rail for their laxity and ease in an era where their enemies were rallying around concepts of conservatism and purity. And they sought refuge by fusing with a deep periphery realm, and began producing armed industrials (see: Reptar, Arana) to try and bolster their strength.
Then, the next glimpse of any sort that we get is a rulebook that uses a theoretical Coyote invasion of the Imperio as a demonstration for how the rules would work. Canonocity of this is dubious at best, but it does not bespeak a mindset of Scorpion strength. Additionally, at this stage of the game, without foreshadowing, without something to prime us for their reappearance, the sudden presence of a homeclan faction is going to feel like a bit of an asspull. Not that these things (cough cough GoT Season 8 cough cough) don't happen, but I think there's a lot of awareness lately that deus ex machina like that make for unsatisfying stories.
And Lets say we DO get a Grand Wolfpack Reunion.
TRO 3145 is our most-recent accounting of forces. Certainly things have occurred since, but it's the most recent option we have, and still valid for some of these forces.
Wolf Empire: 14 Galaxies. 7 of which are wholly second-line garrison forces.
Wolf in Exile: In 3145 was 3 galaxies, but after the fall of Arc Royal, we can hope for, perhaps a galaxy worth of survivors. More likely a couple of clusters, but if the focus was on evaucating personnel, it might be able to reconstitute them to a galaxy worth. Dire straits, but perhaps that will make them more amenable to reunion.
Wolf's Dragoons: 3 Regiments, 3 Battalions. So, roughly 4 Regiments of strength, presumably those three seperate battalions are organized loose for operational reasons. The Field Manual indicates that they still field large quantities of Clantech. Converting that roughly to clan org, let's call that 2-3 Galaxies of strength
Snord's Irregulars: If somehow they were convinced that their distant clan origins were reason enough to return, they would bring another Battalion to the table. Relatively speaking a drop in the bucket. I'd consider this a rather weak link and weak possibility.
Steel Wolves: 1 Cluster, if they could be courted
Wolf Hunters: Already Absorbed.
Brings us up to rouglhy 18 Galaxies of strength, 7ish of which are going to continue holding ground, leaving 11 to do the frontline work. That seems like more than enough to stay the Falcon Tide, and mount a credible trial for Terra to me. Especially if one considers that the Horses have ample reason to hold a grudge against CJF and are flush with the spoils of the former Wolf OZ. The Falcons may find themselves barred from Terra by one set of wolves, and their hometurf imperiled by Horse Revenge.