I thought I'd try make some healthy ice pops - actually my first ice pops too!
I did the watermelon first and let it freeze for about an hour before I added the pineapple.
I must say the fruit loses a bit of their flavour when frozen, mostly the watermelon but even the pineapple too, so next time I'd substitute watermelon for other fruits with stronger flavours, like mango or kiwi and see how they turn out.
These are good for a hot day. :)
After making banana icecream, I would even try a layer of banana in the ice pops, and the banana doesn't lose any of it's flavour at all when frozen.