Your Canoness will do much better with a Cloak of St. Aspira, giving her that 2+ invuln when she needs it.
Your Inquisitor has no use for that inferno pistol, it's wasted points. A plasma cannon shooty retinue is fine, but a 6" weapon inside that retinue doesn't make much sense - you're gonna have to customize the =I= model because they've kitted them out with garbage gear. I think you need more wounds in your retinue regardless - some acolytes, familiars, or whatnot will help it not die instantly.
The ISTs with meltas do nothing at all for you. They're 1 point less than a Sister with the same anti-tank power, worse guns, worse armor, and no faith. Same with the flamers. Especially since the SoBs can have a heavy flamer that uses divine guidance... ISTs with flamers when you could have SoBs with flamers instead is just crazy. The plasma gun squad is alright, since they give you something Sisters can't have, though their fragiliy is still a major downside.
I think you'll find that Seraphim are a lot more powerful with flamers. Inferno pistols limit them to tank hunting and terminator hunting. With divine guidance flamers they can take out most troops in the game very well. 5 girl squads are too small, they are too big a target and too fragile. You should use 8 girls with a VSS so they can get both SoTM and DG most of the time, as well as eat a few shots. With 5 girls, even using Spirit of the Martyrs they'll hardly last any time at all before going non-scoring.
