There is no need to cut delphinium as long as it is green.

Mine also flushed greenish this year... Mine grows around 1" a year or just a little over. It doesn't reflush. After the flush fades, it's a light green. It's a nice little conifer, but mine has been less than spectacular that last 2 springs. It can't hold a candle to Picea glauca 'Pixie Dust'. If 'Daisy White' does flush white, once it starts to fade to green it'll turn pretty quick. 'Pixie Dust' on the other hand flushes for a couple weeks, when the flush starts to fade, the needles have a nice somewhat two tone effect, then it reflushes later during summer. Maybe the weird springs have more effect on white flushers than yellow flushers. 'Daisy White' is the only white flusher I have so I can't do a comparison.

Tiny tidy bugs isn't a lot to go on, but I'm going to guess aphids. Soft bodied, slow moving, pear shaped? You don't need to do anything as drastic as cut back your plants, while they seem to appear by the hundreds almost overnight, they are easy to control. Knock them off with a spray of water, wipe them off with paper towels and squash, use an insectidical soap for heavy infestations. Continue to be persistent until gone, just a few remaining can turn into several dozen very quickly. Natural predators are ladybugs and lacewings. Tip: Do not over water or overfertilize - aphids like plants with high nitrogen levels and soft new growth. Here is a link that might be useful:

Yes, many different shasta daisies. "Snowcap" is about 14' high and the blooms about the size you mentioned, but in my zone 5 it dies back to the ground each winter. I don't know of any Daisy that would remain evegreen in any PA zone. Another even shorter one is "Tinkerbell" at 8 inches, but again it won't be evergreen in this part of the country.