Hello Ritesh,
I do not have complete information from your question.
For the Question 1 - Try deleting the storage bin using LS02N or delete the entry in table LQUA. [Not Sure if it is recommended, but I used to delete]
Question 2 - Move back the stock where it is picked from. If you see this is excess stock, then delete the entry in table LQUA.
Question 3 - There is SAP report [I don't remember the report ] to clear the stock from 916. search for that and try running the same.
Thanks,
Sai Arala.