ET restricted or not. Orochimaru is the strongest.
SM Jiraiya if ET is restricted. If not, Orochimaru.
How can you decide which one of the 3 is the strongest if you are restricting Oro's power XD? I mean, seriously. People tend to create threads 'who is stronger', restricting jutsu from one competitor and with it trying to prove that A>B.
It's just stupid.
With ET, Orochimaru. Without it they are more or less equals.
Edo Tensei is using someone else as your power. I don't believe in it.
Sage mode is using nature power. Summonning a frog is using someone else as your power. I don't believe in it. Stupid, isn't it? And it sounds exactly the same as your argument. Oro spent many years trying to learn and perfect Edo Tensei just the same way Jman trained his SM and other jutsu and therefore it IS his power because he can force dead people to fight for him.
SM Jiraiya >= Orochimaru > Tsunade.
SM is gathering natural energy. All three have summons so it evens out.
But why do you want to even it out? Doesn't the OP want to know who is the STRONGEST one? If you want the Sannin to be equal in terms of power, restrict what you want. But if you want the truth about who is the strongest, stick to the facts.
Using someone against their will as your power? Nope.