V1 would be a decision speed, ie go, no go. V1 will never be below Vmca and on most light twins V1 and Vr are the same speed. V1 is also dependant on runway length so a takeoff from a short field (not balanced field) is probably not legal as V1 would not ensure a stop using only max braking to stay within a balanced field length. Blue line is best single engine climb speed so to go below that would entail accelerating to climb efficiently, which would probably mean a slight sink rate until blue line is reached on an aircraft with one donk on the critical list.
Everyone survived so well done to the pilot. Anything more is gravy....
