Congrats to the proud new owner and to those w. a dream ;-)
Test paddled a Willow just when it came out in 2007. At 5'3" and 115 lbs, supposedly the "small paddler" for which this boat was designed. It's very well finished. Though it tracked well, it just kind of plodded - not very lively or responsive. Too stable/too wide for me. I did a bunch my usual test strokes: low brace turn, different sweep stokes, a few bow rudders and paddled backwards for fun. It just had a fractional lag. Coming from a Mystic you might be underwhelmed.
Based on what you wrote and the boats you are considering,
I kinda think the Cypress or the Impex Montauk might be promising. The Montauk is a proven hull, it's been around for over 25 years if you consider it for what it is, a descendant (copy) of the Shoreline design by NorthShore kayaks. The early Cypress reviews have all been good; I am a skootch large for it and haven't paddled one. I know two women ~45 lbs bigger than me (hope that is OK to say) who paddled the Cypress and flat out love it, one bought hers last August, the other cherishes the same dream as Hapi (Deb)
If you must stay under 16 ft., might as well throw in the Necky Eliza ( fglass version) which is 15.5 feet. Even tho it's conceptualized for women, it's selling very well w. men.
I paddled w. an Eddyline rep when the Fathom LV first came out. He was paddling it. He goes 6' 190 lbs so you will have plenty of room. Wish Eddyline would make a true LV boat. To my eye the back decks are all too high. Their workmanship is beautiful & the thermoformed finish holds up extremely well in boats I know to be 5 years or older.
Those are all very nice kayaks you are considering. there's nothing magically right about a boat less than 16 feet and you certainly have the size to drive one 16 feet or longer.If you can be coaxed to try boats over 16 ft, it would open up a whole lot of other possibilities.
As to hard chine vs. soft chine, my kayak happens to have a medium chine, yup those exist. See what feels good and moves well under you, that's more important than the chine.
Trust your instincts while you demo the hell out of everything.