Since the help file says a spirit in animal form, how about it's a fragment of the caster's spirit that breaks off and forms a magical creature. That would explain why it's ok to conjure them and why it costs 1/3rd con when they die.

As for conjure servitors, my argument for them to be allowed into entropy is similar to this one. It goes by saying that when they're bound by the conjurer, it's more like making an agreement with them, through magical means and that they're going to get the chance enjoy some things that they normally wouldn't, ie healing a goodie, killing evil, destroying, or murder, etc. As example, I bet an angel gets bored as hell (pun intended) sitting in Elysium with no evils to kill. As a result, even when bound, they can't be ordered, so they're still autonomous for the most part but the magical agreement allows some skills/talents to be coaxed from elementals since they're a little less sentient, but conjurers still lack the ability to "order" them around, ie, while bound, they're choosing to stay by the conjurer. If they get annoyed at something the conjurer says/does, etc, then they can kill or attempt to kill the conjurer. I really think conjurers, for the above reasons, should be allowed entry.

IMO, this is far more entropy-like behavior than raising the dead, including spirits, to where they can be ordered around at the whim of the magician. I always associated the "order" command more with a lack of freedom than I did with bind.

If the conjurer help files are the problem, where it says bind into service, how about anchoring them onto the prime plane to work with the caster. Which could segway right into Kaubris anchor, later.