Outdoor 3 1/2 Months w/Pictures

I have 9 plants 1 is about 7 foot tall the rest around 4-5 foot, 1 has stopped growing and began to bud the other 8 are still growing (This includes the 7 footer). Now i've had them all for 3 1/2 months i'm curious as why this one plant is so much taller and thicker than the others, and why is this other plant budding while the rest continue to grow? Another question on my mind is what would be an estimate on the yield of a 7 foot plant with a stem about 4-5 inches thick? Also they are all females i had 1 male but hes long dead RIP.
Here are some photos i'll be taking more soon.

http://i688.photobucket.com/albums/v...Stoner/011.jpg

http://i688.photobucket.com/albums/v...Stoner/003.jpg

http://i688.photobucket.com/albums/v...Stoner/005.jpg

A lot of different factors can make them vary. The biggest of course is different strains. Outdoor they take quite a while to finish, 5 months easy.
A healthy outdoor 7 footer can produce a pound of dried and cured weed.

The strain is a huge factor in just about every way you can think of....we are past summer solstice so they will start to flower whenever they are ready. I wouldn't be concerned just because 1 is flowering now and the rest aren't. It isnt uncommon for an outdoor 7ft plant to produce up to a pound and in some cases more, but just like I mentioned above....the strain has alot to do with that too.

heres some good grand daddy purples