The text for the Scion of Sanguinius Ability for Blood Angel Sanguinary Priests in First Founding states "[a] Sanguinary Priest possesses this ability [scion of Sanguinius] in addition to the three Apothecary Special Abilities listed on page 69 of the Deathwatch rulebook." (emphasis added)

So by the RAW it seems that Sanguinary Priests have 4 special abilities: Guardian of Purity, Create Toxins, Enhanced Healing, and Scion of Sanguinius. I think this is probably a typo, but it would also make Apothecaries more combat-capable and powerful if they got all their special abilities rather than picking one. And until we get errata, Sanguinary Priests DO get all 3 plus their own special one!

I mean I really can't see this as unbalanced compared to the uncontested stuff obtained by Assault Marines, Devastators, or any kind of Librarian...

Anyone see imbalance if it's actually run like this?

I'm sure it almost assuradly means in addition to the three choices a normal apothecary is allowed.

From a rule-centric, RAW, and technical standpoint, the sanguinary priest is an advanced speciality, meaning you can only choose it after you've chosen and developed your primary speciality. Which means after you've applied basic speciality modifications, acquired wargear, and picked special abilities. Advanced specialities would be chosen at the "spend your 1000XP" step, as they require xp to purchase. That step comes after selecting special abilities.

From a RAI and basic sense standpoint, I seriously doubt the developers intended to give a free pass for a player to acquire ALL the special abilities. It just goes against the intent and spirit of the main rules.

Who am I kidding, even with all 3 abilities, Apothecaries would still suck.

I might just give Apoths all 3 in my games. It certainly unbalances nothing and gives them some potentially fun Toxic stuff in addition to the required healbot-plus power.

Well thats fine. House rules are ok, I was just going by official rules.

Have at it.

You're right that I forgot the operative order of chargen. The quoted text just seemed clear to me to be either an operative written workaround or some arcanely-worded piece of stealth errata to benefit Apoths.