There is little danger of either the butterfly bush or the rose bush suffering lethal damage from freezing weather.  If you prune the rose bush now, there is a danger of new growth before a heavy frost.  That new growth would probably suffer frost damage.  In fact, the best time to prune both of these bushes is in late March or early April before new growth begins or just as new growth is beginning.
Don't hesitate to cut the butterfly bush back drastically.  You can also prune the rose bush heavily if needed, or simply prune it to produce a more pleasing shape.
LS