These shrubs would best benefit from replacement or renewal pruning, which removes all branches down to about roughly a foot or so from the ground. Attached is an example of a renewal-pruned old Yew at Brookside Gardens in Montgomery County. Sometimes such plants rebound well, and occasionally they do not, so it's hard to predict how successful that would be. The yews pictured are in very stressful site conditions, and the dieback visible could have been due to winter conditions or a consequence of the past two years of (ongoing) drought, unless they were watered periodically. Root competition with the English Ivy is not helping. If you replant, give the new shrubs more room away from the wall so their roots have more growing space and access to oxygen and moisture.

There isn't much else you can do to help the current shrubs rebound, other than watering as needed (the linked page has guidance) and pruning out the dieback. The overnight freeze of last week damaged young growth or buds on a variety of tree, shrub, and perennial species, so that may set them back further on the road to recovery. They probably do not need fertilizer, but you can have a laboratory soil test performed to measure nutrient levels and acidity (pH) in case adjustments would boost root health.

Miri