Who is your hardest and easiest boss from each stage in the series?

[Zetzumarshen]

Easiest :
1. Rumia
2. Chen, Cirno, and Parsee are equally easy
3. Yuugi
4. Marisa (IN)
5. Reisen
6. Yuyuko - closely followed by Kanako
Extra : Flan

Hardest :
1. Yamame
2. Kogasa, but it is not that too hard
3. Glowing bullets, earthquake, and not-so-safe safespot, please spare me!
4. Aya, or Murasa
5. Shou
6. Oh God please help me it's Byakuren coming
Extra : Koishi

[Aisha]

Hardest:

1: ?
2: Mystia, but only because of Poisonous Moth's Dance in the Dark on Lunatic.
3: Tie between Keine, Nitori, and Ichirin. Again, only on Lunatic. Their lasers freak me out.
4: Initially I wanted to say Prismriver Sisters, but then I remembered that you could choose the order, so none really. Marisa's Lunatic Asteroid Belt can be a bitch, though.
5: Shou. Stupid fireball bullets.
6: Kaguya. Erin's Apollo 13 and Hourai Elixir spellcards are a pain on Lunatic though.
Ex: Probably Flandre, but only because of my perfectionist approach to the entire stage, where I'd refuse to bomb (except during Patchouli supergraze) and would restart if I died or didn't properly graze the things that I had planned on grazing.

Naming the easiest ones is harder than naming the hardest ones, so no.

[Ragnarok]

easiest:

1: ? all are quite easy
2: propably Cirno
3: Keine
4: Murasa, except for her time spell it ain't that difficult
5: Sanae
6: Remilia (because i bet her with just losing 1 live ) and Kanako except for the final 2 spellcards nothing really difficult (havn't figured Heaven's Stream "Miracle of Otensui"  out yet...)

hardest:

1: first bosses...
2: Kogasa, i am to stupid for her final spellcard
3: probaply alice since she got more than one nasty move
4: hmm reimu (IN) i the bullets and orbs are way to random for me^^
5: Orin und Shou, damn those zombie fairies and shou has to many nasty lasers
6: Kaguya and byakuren, kaguya has some god damn spellcards, same with byakuren i simply HATE Light Magic "Star Maelstrom"  i am to stupid to avoid them -.-

can't talk about extra i only manage two or three life bars^^

[Spidere]

Easiest:
Stage 1: Minoriko
Stage 2: Cirno
Stage 3: Alice
Stage 4: Murasa
Stage 5: Shou
Stage 6: Kaguya
Extra: Yukari

Hardest:
Stage 1: Nazrin
Stage 2: Kogasa
Stage 3: Ichirin
Stage 4: Patchy
Stage 5: Youmu
Stage 6: Remilia
Extra: Koishi

[Jinzal]

Easiest:
1:Sara,you can stand still almost the whole fight
2:Parsee,I've allways found SA bosses easy
3:(PCB) Alice,not really anything hard
4:Satori,seen everything before
5:Sanae,nothing hard here
6:Tough one,either Utsuho or Hijiri,I can beat them both with 0 bombs and 0 lives lost
EX:Suwako,nothing hard here

Hardest:
1:Minoriko (not really hard but had to pick someone)
2:Kogasa (not really hard but had to pick someone,again)
3:Ichirin,NOT THE BROFISTS!
4:Reimu,Ying Yang balls of ultimate destruction
5:Sakuya,gotta love those randomly flying knives
6:Yuyuko,for some reason I can't dodge her patterns
EX:Koishi,only EX boss that can kill me before the first spellcard is over