Hi ooffii,
I'm not as expert as others on here, but will try and help.
Yes (i'm pretty sure) you can use your milk and cheese for cauliflower cheese. I would times each items weight by four and make sure you only have a quarter of the dish. This should then count as your two healthy extra A's.
For Roast pots... peel and chop spuds, par boil for approx 5 mins. Lay out on some kitchen roll to dry off a bit, then put onto a baking tray, spray with fry light, and cook for 40+ mins until nice and crispy in oven at 200 (can't do degrees thing!). Check on them after a while and give them a shake around! I made some the other day for non-slimming pals and they loved them!
Good luck!
x