Elena, here are my suggestions- (watch the weather before you go- you could get highs of 85* sunny days or highs of 55* cloudy wet days)
Trash compactor bags- yes, they work great
Rain pant (his)- don't need any (unless heavy rains are forecasted the whole time you are out) you’ll dry quick without anything
Hat- Tilley AirFlo (REI) 3 oz but a great hat and will keep sun off head ears and neck
Underwear (his)- just use running shorts with a liner
Shorts- running shorts with liner
Long Johns- I would get a pair of merino UL as a base layer to work with the running short on colder days.
Double Rainbow- great
Pillow- if BPL get the 2 chamber one
Styrofoam cup- NO WAY- It won't last (I've tried it before), if you need a cup use a plastic McDonald’s soda up (too bug for me)or some other UL flexible plastic cup. You can cut the bigger one down and use sand paper to smooth the edge and it will weigh about .5 oz, not much different then the foam better they don't crush!
Platypus 1 lt (2 ea)- just carry one Platy 2 lt each (lighter than two 1 lt)
Compass- Suunto M-3D (REI carries it)
Whistle- Boaters World in Bellevue has the same whistle as BPL and you don’t have to pay for shipping
Deet- REI Jungle Juice repackaged
Lipbalm- personal choice
Shoes- Inov8 roclite 315- my choice
Cap- see hat above- but I would have a UL fleece (1 oz) cap
Hiking poles- lightest you can afford
Gloves- a UL mitten shell is a good idea if bugs or colder weather/rain comes in (helps the liners keep you warmer)
I Hope this helps- have a fun trip