Sounds like a great plan, bringing both packs home. REI is awesome that way!
Your list does look totally pared down, with no luxuries. So it's just a matter of replacing some of what you own with lighter weight alternatives. By "multipurpose" clothes, I just mean items that can be used in multiple settings.
Here is my (tentative) clothing list for the camino:
(May-August 2015 on a pieced together GR10/Norte/Primitivo/Fistera/Muxia/Costa da Morte/Ingles route)
Walking in (in general, fair weather):
Macabi skirt (also for evening, as it sheds water/dirt so easily it needs little laundering)
technical tee
bra/Wickers (long "boy shorts" undies - anti-chafe for skirt hiking)
trail runners/low-profile synthetic socks
bandanna (for tying back hair, washcloth, napkin, soak in water to cool down, etc)
hat (undecided - hate hats, but need sun protection, have yet to find system I love - though I do love my umbrella -
http://www.golite.com/Chrome-Dome-Trekking-Umbrella-P928.aspx - I use it for sun protection on long, gentle, exposed trails/roads, as well as for gentle rain)
Carrying:
Crocs (shower, beach walking/swimming, evenings)
extra bra/2 extra Wickers/2 pr extra hiking socks
med weight long underwear (black, v-neck top - use as warm base layer, leggings/outerwear top, pajamas...)
2 tech tees (one "nice" one reserved for evening/rest day/sleep - but could hike in it if necessary)
sarong (skirt for evenings, but also towel, sheet, shawl/wrap, privacy screen, etc)
light nylon shorts (swimming, sleeping, laundry-wear)
fleece "warmies" (gloves, beanie cap, buff, sleep socks)
100 wt full-zip fleece hoodie
wind shirt (1 oz, worn alone or under fleece for extra warmth)
Packa (rain gear, also outer shell for extra warmth, belted w/ strip of velcro if wearing w/o pack)
(Undecided on also bringing zip-off hiking pants, and light long-sleeve button shirt)
Like you, I hate mummy bags. I'm slightly claustrophobic, and a side-sleeper. I need a full-zip, rectangular bag or liner, which I will still usually just use at least partially unzipped. There is no way I will spend hundreds of dollars on a super-lightweight , down bag that I will never zip myself up in.
My current liner, which I was planning on taking (I just sleep in extra clothes if it's cold, or no refugio blankets are available) is microfiber, rectangular and full zip. It also weighs 21 oz, so on the heavy side for a liner. I'm eyeing this as a possible replacement -
http://www.proforceequipment.com/product-details.php?id=203&catid=4 It's 27 oz, but still light for a bag, with more warmth than a liner, and it opens up fully to a blanket. Perfect for me.
It's great to shop REI if you're a member and earn dividends. Here are 2 other good online sources for clothing and gear:
http://www.campmor.com/ (cheap year-round, great & easy returns)
http://www.backcountry.com/ (great customer service, usually pricey - but have twice a year 20% off sales)
cheers,
Caplen