I've found that fight to be nigh impossible without items, even more so since you don't have access gotten to the postgame where its possible to IV train. The last puppet in the last battle is S ranked in every IV and has max EVs in every stat (not possible legitimately). It also likely has a condition known as good AI, meaning it will pick its move after you pick yours and guarantee a super effective hit.
I actually figured out a way to do it using S Yuki and D Suika. I give S Yuki Fluorite + Field Barrier + Field Protect + Changeling, and invest in EVs so that she isn't 1HKO'd by S Hijiri's Shooting Press. I use Field Protect at the start and
Shinki switches to S Hijiri due to Shooting Press being SE. In over 30 tests she always switched out S Junko. Field Protect turns Shooting Press into a 3HKO (barely), so S Yuki can use Field Barrier, then Changeling to break S Hijiri's Black Choker and switch in D Suika. D Suika has Battle Mania to lock in S Hijiri, Rations for recovery, and Strenuous Stance + Strike Shot + Aura Drain + Burn Strike for moves. Strenuous Stance gets used twice to put Focus Attack at +4, after which Aura Drain KOs S Hijiri and heals most of the damage done while buffing. The ace gets sent out next, as it has a SE move in the form of Ultra High Tone. With Field Barrier up, it's barely a 3HKO, and a +4 Aura Drain 2HKOs while healing off most of the damage done again. After KOing the ace, P Mima gets sent out, which gets 1HKO'd by +4 Burn Strike. D Suika needs to have EVs in Speed in order to outspeed P Mima, and needs to outspeed P Mima because Luminous Flux will KO, Field Protect is expired by now. The remaining puppets are all 1HKO'd by +4 Strike Shot. The battle takes 12 turns with this strategy. D Suika needs to be level 60 under the assumption of a B- in Focus Attack in order to 1HKO S Junko 100% of the time with a +4 Strike Shot, otherwise there's a possibility of missing the 1HKO.
Basically it generally goes like this
Start with S Yuki,
Shinki sends out S Junko
T1: S Yuki uses Field Protect, S Hijiri is switched in
T2: S Hijiri uses Shooting Press on S Yuki (~49%), S Yuki uses Field Barrier
T3: S Hijiri uses Shooting Press on S Yuki (~98%), S Yuki uses Changeling, switches in D Suika, whose Battle Mania locks S Hijiri
T4-5: S Hijiri uses Shooting Press on D Suika (dunno why but this is her favorite move here), D Suika uses Strenuous Stance
T6: S Hijiri uses Shooting Press on D Suika, D Suika KOs S Hijiri with Aura Drain.
P Shinki is sent out.
T7-8:
P Shinki uses Ultra High Tone on D Suika, D Suika uses Aura Drain and KOs
P Shinki. P Mima is sent out. On T8 Field Protect expires.
T9: P Mima uses Over Ray on D Suika (does almost 33%), D Suika KOs with Burn Strike. S Junko is sent out.
T10: D Suika KOs S Junko with Strike Shot. P Yumeko is sent out.
T11: D Suika KOs P Yumeko with Strike Shot. P Sariel is sent out.
T12: D Suika KOs P Sariel with Strike Shot
Presently my party composition is
P Tenshi
A Raiko
A Kogasa
D Suika
S Yuki
The combination of P Tenshi, A Raiko, and A Kogasa is very solid and can clear every fight in the main story under my restrictions except Yuuka,
Mai, Yumeko, and Shinki, which the other two help with. Other puppets I've tested but found nonessential are E Marisa and S Yumemi. E Marisa's pretty good overall, S Yumemi was nigh useless all the way up until
Yuki, where it can actually solo, although a few other puppets can also solo that fight, such as P Futo.
Almost forgot I had Yume no Kakera, on my desk and not installed for a couple of years. Rectified that today upon seeing this thread ;D.
Quick question: It seems the expansion can detect a completion data of the base game. What's the file it's looking for and where does it need to be?
It wants the save file of the base game, but I don't know where to put it, maybe the save folder?
