wanted to check whats the best method before i start pruning at end of month

hydrangea, cut out all dead stems & then down to 1st or 2nd healthy bud? thing that confuses e is hydrangea's usually have two buds either side of each other on a stem, do these count as one or two? i believe its best to wait till mid march for pruning?

sedum, just cut last years flower stems close to ground as possible? when is best time as i can see new growth just starting

buddelia, cut off dead stems, and then all stems cut back to first bud. Question is does it matter what size bud is, as some stems have very tiny buds near main stem which don't seem to be doing anything, whereas i've noticed a few buds further up stem which already seem to be growing. Again when's best time?

thanks for all your help