Here is what I used for my JMT through hike last year.

Base layer: Merino wool SS T-shirt, 5 oz.
Mid layer: Home made LS, 100wt fleece 1/3 zip pullover, 7.5 oz.
Insulation layer: Montbell inner down vest, 5.5 oz.
Wind layer: Home made 1/3 zip, hooded wind shirt, 2.8 oz.
Rain top: DriDucks rain jacket, 6.12 oz.

On a few mornings when the temperature was around 27°F, I would wrap my sleeping bag around my shoulders for extra warmth.

For the bottom half, I used GoLite hiking shorts (4 oz) with built in brief both as hiking shorts and as underwear. I also carried a pair of light nylon cargo pants (12 oz) as wind pants and bug and sun protection. I also carried a pair of Capilene long johns (5.8 oz) for cold weather I never saw.

a) Your poly SS shirt is the equivalent of my Merino shirt.
b) Your Capilene LS shirt is not quite the equivalent of my 100 wt fleece pull over but probably good enough.
c) Your heavy weight fleece is at least the equivalent of my down vest; but, lots heavier.
d) Your softshell is roughly the equivalent of my wind shirt but again, heavier and probably not quite as wind proof.
e) I suspect the Merrell rain shell is functional but perhaps heavier than the DriDucks. DriDucks are also inexpensive and a full rain suit only weighs about 10 oz. You generally don't have that much rain to deal with in the Sierra in the summer.

I would consider something lighter than the REI fleece, the softshell and the Merrell. Otherwise, looks well thought out.

Added as an edit: GoLite makes a good, light windshirt as do some of the site sponsors for this forum. If you are handy with a sewing machine, or choose to become so, ThruHiker makes a good windshirt kit.