Would it be possible to follow this tutorial with:
1. The UnleashX Dash instead of EvoX
2. No modchip, just a softmod

I want to follow this tutorial because I'm by far not technologically minded enough to do this one

The first tutorial is how to format a HD through FTP. You have to have a modded Xbox to do that.

You need Krazie's Ndure and a game to run the exploit. Other than that you are looking at a mod chip or buying a modded Xbox if you don't feel comfortable doing it yourself. You can look in the B/S/T section here to see if someone close to you can do the softmod. Without putting in a bigger HD you can get it done for next to nothing.

Forgot to say, but you might have guessed already, I'd like to swap my xbox HD with a bigger one, so if i put a bigger one in and use this to format it, would it work like the first hard drive?

The only way to put in a larger HD is to have the Xbox modded. You can softmod it or chip it. After you softmod you have to use Xboxhdm to prep and lock the drive. With a chip you can use Slayer's. After you get the original Xbox modded, you can upgrade the HD.

The xboxhdm thing seems quite good but my question still hasn't been answered, I have an UnleashX softmodded xbox, can I use the format HD via HTP tutorial with an UnleashX softmodded xbox?

You require a chipped or flashed console to follow that tutorial. A softmod won't cut it.