1. They prefer tactics in the manner that they like to have everything thought out, rather than just charging blindly into combat.
2. Quasi-Souls believe themselves to be inferior to other forms of life, those that are not in the "limbo". They prefer to stay hidden with others of their kind, but that doesn't mean that the monastery priests will turn someone away in their time of need, as long as they who they help does not mind their presence. Nor will the cult acolytes just stand by when there is a perfect opportunity to slit the throats and chop the heads off their "superiors".
They prefer to stay hidden, but will come out if they believe they truly should.