On the subject Anyone know what tool I use to get the Cassette Freehub Assembly out marked with red arrows.
Should be a 12mm Allen key.
Sorry don't mean to be rude, are you serious a "Allen key" have you looked at where I placed the red arrows...
This is not a freewheel hub where it is released with an Allen key (Like some), A Allen key has 5 sides, hex shape, the 2 marked with red arrows don't resemble an Allen key at all...
EDIT, after a little searching, you need a tool that Shimano used to make, called a FH-40.
Thankfully for you, Park Tool make one, its called a FR-2