OK, here's some weird stuff for CHEATERS!!! Cheaters who like to explore/break games rather than dominate games.
After figuring out ways to save party members from/avoid the deaths of NPC's in Franziska's realm, I did this:
Started a new game.
Talked to the Reaper(opening Katrina's Realm.)
Saved.
Used RPGM Save Editor to give myself the Firestone(?) seal(which will allow access to Franziska's Realm when I break it) and an Eldritch Tome.
Loaded the save, Broke the Seal, Entered Franziska's Realm, got my party members.
Saved.
Spammed Save and used the Eldritch Tome until I went to the Void, got the Scroll of the Void and the Strange Ring, returned to the Cerulean Fields and sold the Broken Seal to the Reaper.
Saved.
Used RPGM Save Editor to zero out all switches and variables relating to Franziska(as not doing so will make the Reaper think you've already defeated the first 5 Dominas and(potentially) result in game-breaking lack of interaction. The Reaper did NOT act as if I was trying to help Cicero(the Merchant in Narcissa's(yum) Yonder of Disease... so I wouldn't be surprised if the Reaper wouldn't act in the way he needs to in order to beat Mary's Realm.
Loaded the save and played as normal, except now I have 4 party members.
Naturally, I chose the Arcanist path.
Without cheating any more:
-Only 3 Party Members can accompany you into battle. The fourth will not gain EXP or Mastery Points.
-Doesn't seem to be a way to add/remove active party members. Jerry is stuck getting no EXP or MP.
-Party members have no ability to be Equipped and no Combat Special, Skill, Mastery or Proficiency other than Attack, Guard and Item. They become more Proficient in unarmed combat, but I'm not sure what advantage that gives you.
-As with most RPGM games, Party Members who have dropped to 0HP get no EXP when a battle is won.
-Active Party Members Level up with less EXP than MC. Other than a VERY small number of boss battles, I've kept everyone alive and my most recent save has MC at LVL 30 while all my Party Members are at LVL 34.
-Eldritch Tomes which increase stats affect ALL party members, INCLUDING Jerry, who is stuck gaining no EXP or MP. This is not the case when advancing through Skill Trees and getting the Reaper bonuses after losing all your Soul Shards. Only MC gets those perks/bonuses. Other than learning Eldritch Blast, Eldritch Shockwave and Eldritch Storm... ALL my Eldritch Tomes were used to add +30 to Attack, Defense and Agility(when you increase your Agility enough that you attack BEFORE a Lost Disease Marksman, you WILL attack BEFORE Narcissa, which makes it WAY easier to beat her.) I used my Reaper bonuses after losing all my Soul Shards to increase Magic ATK and my Magicka pool.
These aren't super-special... but if you hate Mary like I do... you might be interested to know that before you're supposed to be able to defeat Mary... the effect that Mary puts on MC (loss of 25% Magicka and Adrenaline(TP) per turn) does NOT affect Party Members... and if you've buffed their ATK enough... and especially if you've used Arcane Blastx2(reduces enemy DEFx2)... they can kick Mary's ass when she's not auto-counterattacking in Vengeance State. AND it still counts as Mary beating you, allowing you to advance the storyline in Mary's Realm. Your party won't get any EXP, but you can feel like you gave Mary a big F-U
which I enjoy! Looks like MC';s Stress doesn't increase when you drop to 0HP and your Party Members defeat Mary... yeah, FUCK her!
Now I'm wondering if I'm going to get 4 additional LVL1 clone Party Members when I LEGIT get to Franziska's stage... or if I'll have to use RPGM Save Editor to keep the game from breaking...
EDIT: OK... so with Party Members... I can't use any of Llavanya's Tomes of Light Magic on MC... and they have no effect on Party Members so I have no access to those spells. OBVS, I can already beat the crap out of Mary... so that's not a problem. It'll affect my ability to crush Raa when she's only vulnerable to light spells later on. I'll see if I can use them later on and if not, I'll keep this save to see if I can CHEAT my way into being able to use them.