howard

Hello,
I currently own a Canon 24-70mm 2.8 mark i and the Canon 70-200mm 2.8 IS.  I have decided to get the GH5, but before I make the order, I have several questions I would like to ask for advice.
1. Should I keep my current lenses and buy the Speed booster? XL or Ultra? I inherited these lenses so not sure how good they are.
2. How well does Stabilization and Auto Focus work with the Speed Booster and Canon lenses on GH5 compared to native lenses or other lenses?
3. Would it be better to sell my lenses and get a different setup?  if so, which would you recommend?   Get native lenses or other lenses with Speed booster?
If I keep my Canons, my budget will be just for the Speed Booster.  But if I sell them, I'll have around an extra $2,000 dollars for lenses.
I will be mostly shooting for music videos.
I really liked these videos.  He is using the
Panasonic Leica 25mm 1.4
Panasonic Leica 42.5mm 1.2
Olympus 75mm 1.8
What do you think about it?
Thanks in advance!
-Howard