The flubber loads before the dashboard so it needs a custom bios to disable it, softmods cant do this.
The logo you see for the dashboard loads after the flubber, there are skins available for these from places like xbox-hq or xbox-skins (cant link to them because i dont know if there's anything there that shouldn't be)
Tutorials are all over youtube, if you want to run FBA or madmabs emulators google emuxtras, if you want to run with vision or coinops google coinops5, there are of course others out there but those 2 should cover what you want to do. I have no experience in the FBA/Madmabs stuff so cant help you there, coinops is locked so it's either the lite 5gb or full at 60gb you will need. With Vision you are free to add what you want and make your own packs/artwork, there is also packs available like Visionary that comes in at around 15gb, google is your friend here

PS
Check out FEU3RSTURMs channel, he has come up with an idea to take videos of things like hyperspin and transfer to the xbox as a .xmv video file so you get the hyerpspin experience without needing a meaty PC to run it.
https://www.youtube.com/user/FEU3RSTURM?feature=watch