Where are you geographically? USDA Hardiness Zones indicate only average annual minimum temperatures, say nothing else about the growing conditions in a Zone. (And there is a Canadian hardiness zoning system in use also, with different zonal parameters).

Also what characters do you want the replacement shrubs to have, other than providing some screening? You took the arborvitaes away so there are apparently particular limits on what you want there, that these plants did not fall within.

For the AC, check out this open surround that allows circulation but adds some camouflage. The thread is a link to its reconstruction to accommodate a new AC unit, but you get to see it in place plus out in the open.

https://www.gardenweb.com/discussions/4709513/just-finished-a-small-reconstruction-project-for-the-north-alley#n=5

Combined with the relatively low plantings, the AC unit become smaller far less noticeable without being blocked that without the screen.

As Embo suggested, general location such as nearest large city is helpful since parts of each of the desert SW, the coastal SE, and the PNW all include zone 8 but growing conditions are really different, and similar differences occur within zone 5.