Respected Tripti, hi I evaluated your query thoroughly.
(a) you can apply 
anesthetic cream as many times you want, but specifically
     recommended after passing stools
(b) skin tag will not aggrevate fissures unless there is hard stool
(c) avoid all oily / spicy / nonveg
(d) occasional drinks not recommended at all
(e) no side effects in the hands of experts 
(f) lifetime if you have not much discomfort and symptoms under control
(g) depends upon the procedure performed . normally 3-4 days for simple 
     procedures , more for complicated surgeries .
@ NOT mentioned anywhere about Sitz bath - the cornerstone of fissure
    treatment doing or not advised ??
Hope this clears your doubts
Welcome for any further assistance
Wishing you fast recovery from the same.
Thanks for using Health care magic & giving me an opportunity to assist you.
Regards dear take care.