I think the samurai are being underestimated here; these guys cuts mechs like butter as well as cut and deflect giant bullets fired by said mechs. With only 10 lives they can win scenario 2 and with standard lives, with some difficulty, they win scenario 1.
1. Homunculous Standard amount of lives
2. Battle starts from 20 feet away
3. Battle is at dawn
5. Battle is in urban city
6. Samurais get 2 days prep
7. All out battle
With 2 days of prep but no knowledge they can't really prepare accordingly, however if they know it's going to be a battle they can easily prepare for extreme threats with Heihachi's help, however with the fight at dawn the samurai would need to quickly take out Pride before it gets dark, since they are in a urban city there are likely many alley ways for Pride to hide and attack however with their prep they can likely get access to some heavy machinery such as large guns and traps. Plus with their strength they can likely parry and knock away Pride's shadows. All in all I am undecided on this part, it could go either way.
1. No prep
2. Each fighter starts 10 feet apart
3. Fighters are in character
4. Homunculous only get 10 lives (Except Wrath who only gets one.)
4. One on one with the following match-ups:
Shimada kambe VS. Greed
Greed felt attacks from Wrath while in armor, I think kambe should be able to slice right through it, he is also much faster and more skilled than Wrath who took him down. kambe wins this easily.
Okamoto Katsushiro VS. Envy
Evny just sucks even in his giant form, he gets cut to bits over and over.
Kikuchiyo VS. Sloth
Kiku, stronger and can take more.
Katayama Gorobei VS. Wrath
Hayashida Heihachi VS. Gluttony
Heihachi is too smart for him and too fast.
Shichiroji VS. Lust
He was on part with Kambei
Kyuzo VS Pride
Kyuzo is faster and at dawn he has a chance.
I will make a more detailed argument later but Samurai should win.