What about if fiverr allow us (sellers) to send a mutual request to buyers for little date/time extension on active order. Due to unexpected issues/problem some time order get late to deliver and before this late delivery if there is a way to send a request to buyer to allow some more time then this feature would be very helpful 
Yes! This! Sometimes more time is needed due to many circumstances. It could be added to the new in-gig extras feature. Right now, you can’t request to add an extra without charging more. I just tried to add an extra requiring 2 days time for $0 and it wouldn’t let me.