|: Would you know if you can use any kind shoe in these?
: And I wonder if you need the tall boot support necessary for inlines?
You can use other shoes of a similar shape. Tennis shoes, Vans, etc...
The problem with lowering the ankle support is that you would have to cut through plastic and padding. I could be done though, and if you are used to low profile boots like speed skate boots, then you would have no problem skating in them.
The main reason inlines have such high ankle support is because the wheels are underneath the middle of your feet. This causes the foot to continually want to go sideways, right or left, thus putting terrible strain on your ankle. With quads, your support base is wide, therefor your feet do not need as high a support.
Your bigger problem with quads is truck placement. Too far forward (in the rear) and you'll fall over backwards when standing straight up. Too far back (in the front) and you'll tend to fall forward while skating.