Identification Help Needed

I helped out at the local arboretum today. I helped with re-organizing, weeding, and re-planting the herb garden. They have worked on the garden annually as far as weeding and keeping it in decent shape but it hasn't been fully assessed and organized in several years. The last comprehensive listing of plants in the garden was in 2001 to give an idea of where they are at currently. They have some great plants but so far if my tentative identifications are correct some plants were added between 2001 and now and not everything that was added was an herb plant. So, obviously, that complicates identification if I can not narrow my search to herb garden plants only.

The first plant that I managed to positively identify was French Tarragon. It was positively identified through pictures and also due to the fact that a tag for the plant was found when it was trimmed back. It had grown quite large and overwhelmed the tag.

The second plant that I got a positive or nearly positive identification on was Rue, variety unknown. I didn't find a tag on this one but it is unique enough looking that there isn't much chance of being wrong on identification.

The last plant that I got a pretty solid identification on was Artemisia. It is most likely the variety 'Silver King'. I am not positive on the variety but I am pretty positive that it is Artemisia.

The next plant could potentially be Comfrey or Hyssop but identification on this one will probably be near impossible until it blooms since it is so generic in appearance.

The next plant I found a potential for but am not certain I got this one right. The reason I am so uncertain is that it is only hardy to zone 6a and we are right at the edge of hardiness. Also, it is not an herb.

The plant I found that looks like this one is Cotton Lavender or Gray Santolina. The pictures above are from the arboretum's herb garden. The picture below is from the internet. I could use a second, third, etc. opinion on if they are the same plant. They certainly look like it to me!

The next plant I felt certain I would have found a match for since it is very distinctive. However, I have come up a complete blank on identification for it. The only thing I have found that could even be partially similar is tansy and that doesn't seem like a good match. I think I will just have to wait til this flowers!

Lastly, we have another complete unknown. Again, this is one that I think will need to wait for flowers for a positive identification.

 Other herbs that we either had a complete identification on or I just knew the identity of were chives, garlic chives, fennel, lemon balm, rosemary (it actually survived the winter!), sage (normal garden, not tricolor), apple mint, winter savory, and thyme. Due to need to transplant or plants that had babies I was able to take home some artemisia, rue, chives of both types, fennel, mint, French tarragon, winter savory, and thyme. My herb garden went from being just a normal garden to actually seeming like an herb garden. It is looking amazing, or will as soon as the plants recover from transplant shock.

Any comments on identification can go into the comments section. I appreciate any and all help!!