The exotic beast has been finalised to the Firebird and the Long Term Care rules have been rewritten to make them more worth it (As a 5/6 chance to just shuffle about what long term injury they have and a 1/6 chance to fix it was kinda crud with the cost behind medical escorts). Unless something comes up as needed from later books or people point our balance issues, I think it is safe to call the Hospitalers done as a faction.
Thanks for the feedback people have provided. If any problems come up, feel free to tell me and I'll do my best to fix them.
Exotic Beast has been completed. A fragile but sneaky snake with anaesthetic venom in the form of the Caduceus. It doesn't have any direct 40k models (Though a snake model is very easy to find) but I ended up not going with Cherubim because of the fact Cherubim have opposable thumbs, are clever and are depicted in art and models carrying weapons at times. They ended up feeling too powerful when I wrote up the rules for them.
Boltguns have been moved to basic weapons to line up with expanded lists. Basic armour for the gang is no longer Hospitaler Carapace and Mesh armour but instead Shield Robes (Which can be combined with armour like an armoured undersuit as, since they are flowing robes, you can wear them over existing hard armour). This keeps the 'very tough' aspect of them without putting a massive cost for light carapace on the head of the player for the base cost. Unique rules for meltabombs have been replaced now that we have official meltabombs. Added servoskulls to the base list (As they are an iconic ecclessiarchy equipment and the list was kinda short on equipment compared to the other lists).
Faction Cheaper Equipment
Bolt Pistols (Significantly so)
Shock Whips (Slightly. Here 90% so that people can use old Sister of Sigmar models if they have them, which had a prominent whip weapon)