>>96291304
>Phobos Land Raiders, Castraferrum dreads, Leman Russes, Baneblades, etc.
All these were originally FW models or the rules were designed to encourage players to use the FW versions. That's why HH russes have no sponsons.
>You're confusing FW with GW
No, you are the one confused in the order of events
>Because SA models existed due to one dude and FW took them and ran with them
For one reason only: it was a way to field human troops without using 40k IG models
>Taghmata existed before 40k Mechanicus had models.
Alan knew that 40k AdMech was coming or was told not do it (because Jess Godwin had seniority and first gibs, I guess). Hence him pulling from his hairy ass a force that had never existed in the lore before in 40k or 30k. Btw, 40k AdMech was already a thing in other games.
>What 40k jetbikes were available as an alternative?
The Bullock style jetbikes. Like the one used by Samael, in the early Heresy WS books, or in the custodes models that were also in the pipeline
>Ruinstorm Daemons
Yes the ones whose rules favour without shame their resin models and pretend that the classic 40k/fanrtasy models do not exist despite being featured in the HH books
>IW
The IW signature unit since forever were Iron Havocs. Tyrant Terminators are a rip off from that previous Visions UM art, yes. Probably because back then the authors were also into the UMbad zeisgeist of 5th ed, until Abnett fixed it with Know No Fear

FW basically created their own version of the HH to sell their resin. Which is more or less fine if you squint your eyes and pretend the game only covers a part of the possible battles, I guess. Or it was until the Specialist Games Studio went full retard with retcons, mischaracterizations, and shitty designs. Nowadays the HH game setting is almost an alternate universe to the actual past of 40k and the HH books