I like your approach to the Relictors and I haven't played much but some thoughts, :

- Ability to add more than 1 specialist per SM squad (Apoth, Techmarine, etc...) depending on squad and specialist tier.
- Alternatively, ability to add Mark (banner) + squad specialist.
- Daemonhost doesn't make sense as a Hero unit but as a summon by the inquisitor.
- Alternativley it could be mutated / corrupted space marine or dreadnought.
- Add powerful last tier units (Knight, Superheavy, etc...).
- Ridgehauler is an odd choice of transport. Why not a chimera, rhino, or any of their variants i.e. Kronus pattern Chimera

There are fluff and game play reasons for these.
- The reason for the one specialist per squad is to prevent the creation of a super squad. It probably wouldn't hurt for them to share the active abilities, but many of the attachments have passive abilities that could get really powerful if mixed. In addition, all the space marine units have increasing upkeep the more of one type that a player has and enabling super squads would undermine this limitation.
- From a fluff perspective, the Relictors and other Chapters don't have enough specialists to go around like a fresh Chapter would so limiting the specialist count to one plays into this.
- This is also a throwback to 3rd edition rules change when the Command Squad had all of the specialists and it was changed to allow the specialists to detach as non-independent characters.

Back in 3rd Edition and the Inquisitor Rule Set the Daemonhosts were beefier and more independent than they became in later editions. The Daemonhosts of the radical Ordo Xenos are more reflective of that group of hosts.

The corrupted space marines are the Cursed Knights from the Chapter Approved Cursed Founding Rules and they do a lot of fancy things.

The lack of a superheavy, other than the Thunderhawk, is a deliberate choice. In the quests the late game advantage the Relictors is a second fortress. Between the specialists and units like the terminators and the Cursed Knights they should have enough firepower to replicate super heavies.

The Ridgehauler driven by the Orks is both a fluff and a gameplay choice. From a fluff perspective, the Inquisitors arrived via the webway and couldn't bring their heavier vehicles through and are falling in on the up-gunned ridgehaulers. Its not totally clear right now because I am still working the on the quests narratives, but that is what is planned. From gameplay perspective a chimera is a mobile pillbox like a bmp or a m2 slick and that is not how I wanted the inquisitor portion of the faction to play. The Ridgehauler is supposed to enable rapid maneuver and in the late game some fire support more like a Wave Serpent or a Devilfish. I could have used the Rhino, but with the Razorback already in use, part of the cursed founding fluff that limited their Rhinos, and the changes to the weapons and cargo slots adding in a Ridgehauler seemed like a better fit.

I see, this makes plenty of sense. Like I said, I like your approach to the Relictors and I'm looking forward to trying them out when they're released.