Can you Reknit a planeswalker that will have 0 loyalty counters due to
a) using an ability?
b) attacked by creature?
c) targetted by direct damage?
will Reknit replenish their loyalty counters?
say if someone played Desert twister on a planeswalker I can Reknit it right?
No, I am not a judge. That's why I like to quote sources such as the rules that trump judges.
Sure, why not?