I mentioned that Tobirama could use his water style and FTG together once, I think around 7 months ago?
Most people said it wasn't possibly and they also gave reasonable facts but I forgot what they said >.>
And Madara wasn't experienced with fighting anyone with the type of FTG that Minato has.
Tobirama used some different technique against Izuna because he was able to wound him.
Unlike the regular FTG where you just teleport to something by entering a different dimension and having another dimension pop up somewhere else and come back, Tobirama did something else, otherwise Izuna wouldn't of been wounded.
It was most likely simply some high-speed attack, and it's not too unbelievable because Tobirama was in his prime and he was hailed as the fastest shinobi of his time.
And Tobirama couldn't teleport the alliance out of the barrier because he wasn't connected to them unlike Naruto and Minato were.
Minato himself explained that FTG works by him being able to teleport to wherever his chakra is or where his is connected too. Tobirama's water jutsu is made from his chakra so he can teleport to it. Sasuke's Kirin is made from actual Lightning, thus it cannot be absorbed and is different than chakra based lightning.
Minato's FTG is the same as Tobirama's, you instantly appear to where your mark or chakra is, Minato threw his kunai around the battle field the moment he first got to the war and teleported Tobirama and Hiruzen to their spot to preform the barrier seal on the Juubi, Madara was doing nothing but sitting down and watch since Hashirama said he's deal with him later so he already saw that Minato uses FTG with his Kunais and can see the Kunia be thrown at his feet so using his sensory ability and his Rinnegan, he can react much greater since he knows what to expect much like how Naruto dodged the 3rd Raikage's attack in SM.
FTG doesn't go to another dimension, that's Kamui. FTG is you go to their mark or chakra from where you are instantly, Minato and Tobirama were never shown to go to another dimension. Tobirama can mark his sword, throw it, FTG to it and carry out his attack. Tobirama said he cant teleport everyone when he wanted to help teleport ninjas from danger against the god tree. He was using Minato as a medium to tap into his chakra and teleport a few ninjas at a time since he doesn't have the skills to do is like Minato which is why he said he can't teleport everyone like Minato.
Having more chakra doesn't mean you can accomplish a feat, you need the skills to do so. Jiraiya has more chakra than base Naruto yet is Jiraiya more skilled with Rasengan and Shadow clones than Naruto who created much stronger Rasengans which are much high level chakra control? No, it's the skill. The next generation surpasses the last, this is said in Naruto since part 1.