It would help if you let us know which area of the country you're in. As MadGallica frequently reminds us, there's a difference between moist zone 5 areas like upstate New York and drier zone 5a like areas of southern Wisconsin, or here in Nebraska.

I've grown most of the roses you mention and I'll comment on each for my zone 5 winters. I do agree that in general the Rugosas are very hardy, and I've never ever lost an Easy Elegance rose - they're all tip hardy for me even in this miserable cold winter.

Lambert Closse
Austrian Copper
I haven't grown these two but they're a safe bet for hardiness in the zone 4/5 regions

J.P. Connell - little dieback over the winter so far, though it has taken a while to establish for me. I have it in my zone 4 pocket of the yard and it seems fine for hardiness, but I think it wants more sun than it has in that bed.

Hansa - in general, rugosas are a great bet and this one is highly scented, but I have to say it was a dog for me in my previous yard. A two cane wonder that only bloomed once then lost all its leaves to blackspot even in our dry climate with nothing else planted around it. I've had much better results from Therese Bugnet, or Linda Campbell among Rugosas.

Prairie Joy - grows big and hardy in my zone - droops over a 4' high fence surrounding it, but I don't think it has enough sun where I have it, and it doesn't bloom very often for me.

Quietness - lovely, reliable, hardy, saturated medium pink blooms. Not all Buck roses have been hardy for me, but this one laughs off my zone 4 pocket and reblooms pretty well.

Heaven on earth - you really want this rose. I'd put it among my top 10 favorites among 700 roses. It smells nice, with delicate apricot-pink blooms that are very double and profuse, laughs off the cold in my zone 4 pocket, and stays a nice well rounded 4-5' bush with blooms all down the sides

Pretty Jessica - this one grows fine in my yard and is perfectly hardy, but I haven't seen as much rebloom from this one as I hear reported elsewhere. Austins in general are terrifically hardy for me, and many of them get quite big, so this one is a good choice for a small Austin. Still, I'd pick Sharifa Asma or Tamora or Darcy Bussell or The Prince as a better small Austin that's nicely hardy.

Alchemist - haven't grown this one

Kashmir easy elegance - in general the Lim Easy Elegance line is absolutely the only rose breeder for whom I've never had any winter kill, with 15 varieties and counting. I haven't grown Kashmir among these yet, but its a sure bet. Another Lim to consider that I dearly love is Sweet Fragrance. Big fluffy true apricot/peach double blooms all up and down a 4-5' bush that bloom all summer. The only thing it doesn't have, oddly enough, is fragrance. Still, it's on the north side of my house, which is mostly zone 4 pocket too, and it does so well I put in three more of these (alternating with Music Box) and I almost never do duplicates of roses.

Freckles - I'm putting in a replacement of this one this spring, as I lost one of these over the summer. I wouldn't put this as the hardiest of the Buck roses- Mountain Music, Quietness, or Prairie Sunset/Sunrise have all done better for me.

Champlain - Champlain was my "gateway rose" at my old house that convinced me I could grow roses (had I only grown the Hansa I had on the other side of the house, I might never have planted another rose). It blooms pretty constantly all season, with dark crimson-pink blooms and nice glossy clean foliage. I did lose one once in my new house, with a weak cultivar from a local source, but my present one is strong and healthy. I had to cut it back a fair bit after last winter, but I had to do that for virtually everything but the Austins, Easy Elegance, Explorers, and rugosas (and even some of them), so that's nothing against Champlain. Individual blooms are not good for cutting, but the bush statement is very nice.

Hope this helps!

Cynthia