Don't forget the respirator and protective clothing for spraying 2k
I'd tend to go 4L of colour so you've got extra if you ever need to re-do a panel etc you know it's been mixed to the exact same tint/hue etc. If you get it colour matched and mixed by someone else down the track you may find in certain lights you can slightly see the difference, particularly with metallic colours.
Nothing worse than needing to re-do the panel after a year or so from a scratch or a bump and getting a new batch mixed up thats ever so slightly different. I had that with Silver Ice for a VS a few years ago, two different crash shops both mixed PPG Silver Ice but in the right light you could slightly see a difference between the two.
Buy a good quality body filler if your going to fill the dents (I'd recommnend this route if your not super confident or experienced in repairing dents otherwise you can be left with ripples in the panel etc).
You say you've got some fade, if the clear is starting to oxidise your going to have to get rid of all that. If you spray over oxidising clear it will delaminate after a few months.