Alongside this I'm sorting the rest and am thinking:

bread x 10 baguettes

green salad - lots !

new/warm boiled potatoes - 10lbs
roast veg - not sure how much !
baked beans - 6lbs (a bit of a joke for the guys who love them rather than for all !)

greek salad - 8.5lbs
coleslaw/waldorf/rice/beetroot - 5.5lbs each

Does that sound about right ? And any advice re the roast veg - was goining to prep day before and just reheat on the bbq in tray ..

Grilled or roasted veg can be served room temp- perfectly safe and acceptable. about 15 pounds.

I would count this for estimating purposes as 2/3 of 100.

bread x 10 baguettes- at least 8 pounds, 10-12 would not be too much. Have a couple pounds of butter for the folks who like it.

green salad - see plan for 100, do 1/2 to 2/3 Greek salad

new/warm boiled potatoes - 10lbs- I would do 25-30, you don't have a lot of starch on this menu, and these are a very popular filler
roast veg - about 15 pounds
baked beans - 6 lbs (a bit of a joke for the guys who love them rather than for all !)

greek salad - 8.5lbs-OK, but I would do double and cut back some on the plain mixed
coleslaw/rice/beetroot - 5.5lbs each- OK, you will probably run out of slaw

waldorf - 5.5lbs each- this is very popular, I would do about 2 gallons