As a fellow PNWer and silvopasture manager, I would consider walking around to grab foxglove flowers and stuff them into a trash bag. I ferment noxious weeds in barrels then pour the resulting slurry on gardens for fertilizer--but the crux is that I can't have seeds in there, so get the flowers young if you choose to go this route. My neighbors have severely overgrazed pasture (constant sheep presence for all the 17 years I've lived next door) and it's basically mud and foxglove. So even though foxglove isn't killing those sheep, it's not doing them any good either. Check out Fred Provenza's book Nourishment for great info about how animals learn to forage. Animals new to foxglove might overindulge. Honestly, walking around gathering foxglove flowers is also an excuse to get to know your pasture. More footsteps is more awareness is more productivity.
Orchardgrass is delicious and productive but does not love shade. The best way I have established it is by using horse trampling in the winter. 15 years after housing the ponies in one section of pasture over the winter, it still grows the best orchardgrass which we mow for rabbits and goats before running chickens over it. We get several cutting in a good moist year like this one. I have never bought seed for it, feeding the ponies orchardgrass hay is enough. Word to the wise--several other seeds have come in on loads of hay. Wild amaranth seeds survive a trip through a horse gut just fine!
Buttercup has been a decreasing issue as I have added significant calcium carbonate to the soil over the years. Adding wood chips, for whatever reason, has served to INCREASE buttercup significantly. This is Ranunculus repens, Creeping Buttercup. It tells me about low-drianage low-calcium spots in my land. I have had success in my boggy areas with Korean nut pines from Burnt Ridge nursery. Also some hazelnuts cultivars (ones recommended for heavy soils--get blight resistant or -immune ones!), and raspberries grown on chinampa-style berms created by piling up twigs left by our goats and piling dirt on top. The dirt comes from pondlets dug between the berms, which get used in winter by our ducks. We get phenomenal crops of comfrey and willow by these ponds, which cycle back into the goat pen as browse when the willows aren't getting used for basketry projects.
While I have used sheep and goats and horses between trees, my current favorite is our rabbit tractors. They might be my favorite because another farmmate takes care of them, so all I see is tasty rabbits leaving perfectly mowed and fertilized grass in their wake as they scoot around under the pear, apple, and nut trees.
Are you getting Katahdins? If so, I recommend Michelle Canfield in Monroe. I once heard a sheep in distress in my pasture and found one of my East Friesian ewes firmly lodged in Himalayan blackberry, stuck there by her fleece!