I'm not seeing any resemblance to the Warhawk or Timber Wolf, tbh. Just looks like a Dire Wolf with that weird cowling cut off. Maybe longer legs, but that could just have to do with its art being mid-step. The RecGuide also doesn't say anything about it being based on anything besides "Dire Wolf, but make it go faster."
The cockpit's got a rounded shape that looks more like a Mad Cat's rather than the angular cockpit of the Daishi. I agree with you that it doesn't really look much like the Masakari.
Don't the Dire Wolf and Warhawk share the same hips & legs? Maybe that's what they're referring to?
This is what I see:
While features across designs aren't exact, the inspiration is definitely there. That inspiration originated from the model bashing of the original MechForce design... Which I admittedly can't find on the internet. I must be thinking of what I saw on the Heavy Metal Pro website:
I think it really makes sense from a fluff and visual standpoint that an optimized 100-ton Clan Invasion-era omnimech (400 XL, FF, ES, max engine DHS) looks like a combination of the Timber Wolf (an optimized 75-ton omnimech) and Dire Wolf (an almost-optimized 100-ton omnimech), of which the Warhawk shares visual parts with the Dire Wolf and is kind of an extension of that.
To the point @Jal Phoenix made, indeed only the Dire Wolf basis is mentioned in the RecGuide fluff. While the Timber Wolf or Warhawk aren't mentioned, the inspiration is definitely there in the Iron Cheetah's visual design. To the RecGuide entry's credit, I think that at least the mention of the Iron Cheetah's basis on the Dire Wolf is a lot more obvious than saying the Blood Asp was based on the Kingfisher.
EDIT: Added clarity with respect to visual attributes and merging optimized designs.