Fantastic post. I've been growing 6 varieties for about 5 years now. They're just starting to get big enough to produce a reasonable crop. I use a lot of it, I'm finding it takes about 30 plats per person if you intend to have it daily, but the berries do freeze well.
In terms of propagation, I let my chickens scratch under them. That mild disturbance of the surface roots triggers suckers to come up by the thousands, which can be grown out for a season before being moved.
I'll be scaling up to about 600 plants this year. I'm definitely following your posts.
As for de-stemming the berries, if you can take the whole branch (pruning at the same time), just stick the whole thing in the freezer, and when frozen, wrap with a towel and whack it on the counter. Not helpful for large harvests but for anyone with 3-6 bushes in their backyard, it works great.
I haven't used the leaves for tea, will need to try that. However, the berries are probably one of the best-tasting fruits when they undergo a lactofermentation. Juice them and get a lambic beer culture from your local brew shop, and just pitch it in and leave it on a warm countertop for a week, then add in a bit of honey, cap the bottle and let it set for another two days to build some effervescence. Serve chilled. Also benefits from a cardamon seed in each bottle. It will be mildly alcoholic (<2%), but very refreshing.
Keep up the good work.
RE: Cold Climate Permaculture Plants: Sea Buckthorn