#1- they will still put out some just not as quick as before
#2- that is not normal
#3- not too late just dont go full strength right away cause it might shock them
#4- not horrible/still salvageable use your nutes and everything will be alright
you still have a bunch of white hairs let them turn amber then youll be good should be just as you said 2-3 more weeks so probably start your flush next week
i dont know the actual answer but i just asked the same thing yesterday and found this when searching
https://www.rollitup.org/advanced-marijuana-cultivation/151706-uncle-bens-topping-technique-get.html
theres a bunch of pages but the first few are very helpful
so i got my little plant and was wondering everyones opinion and advice on which technique to use and when i should start it. oh and i guess i also forgot about super cropping
until you can grow you should collect grow books, find the seeds you want, start getting your lighting equipment(theyre expensive), and everything else youll need. so that way when you finally can grow you wont just have one big expense. and you can always grow herbs and vegetables in the mean time