With major glitches would fluddless be possible?

Yea, there are even some runs of it

Yea, I believe this can go to somewhere around the 15 minute mark. Even though I've been on a break for a couple weeks now, I could realistically come back and get something like that within a matter of days. Maybe even a lot lower, as Vertic himself has proved many, many times in the past.

Would tutorial 2 be even remotely possible?

It is possible to complete T2 without fludds, yes. But it takes a long while to do so.

how do you do it?

There is a technique called "Infinite Spin" which allows Mario to gain theoretical infinite height. This technique is used heavily throughout this run to clear what would seem like impossible-to-clear vertical stages.

By pausing at the peak of mario's jump, then spinning and pausing right after, you go into the fludd tab of the pause screen, click on "none" fludd. After unpausing you get a tiny bit of additional height. This can be done indefinitely to gain height.