Answer: Although you can move your butterfly bush now, it would be best not to prune it back at this time. When you prune you encourage new growth which will not have enough time to harden off before winter weather. You'll have to prune it back again in the spring, so why not wait until then to do your pruning? Whether or not you can divide your butterfly bush depends upon the root system and whether or not there are several stems rather than simply one main stem. If there are several stems coming from the root mass you should be able to separate the roots into two or more plants.
Peonies resent being moved and will often refuse to bloom for several years after being transplanted. Since you anticipate having to move them in the future, I'd suggest replanting them into containers rather than back into the ground. The rootmass will be deep but not very wide. Expect to find the majority of the roots within the top 18" of soil.
Best wishes with the move!
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