you can do the whole grow in the current container if you so choose it just depends on how big you want to let it get. The white stuff on your leaves is probably some sort of mildew which you can figure out how to get rid of by searching the forums on this site. All in all I think it looks...
You should post a picture, but it's normal for the leaves to die starting from the bottom. If the new growth at the top looks healthy that is all that matters, and if it doesn't...That's when you want to perform manipulations of nutes and things of that nature.
I have had a Blackberry kush plant in a 16 oz cup for about 2 months without problems....when you star to flower is when the space is going to fill up quick.
They're fine....they grow short and bushy first then get taller. If you top the plan it slows vertical growth and promotes horizontal growth (fat bushy), so if you are looking to get taller plants don't top them....if you want short bushes top them.
When I grow in soil I never check the Ph, and I never have problems. If there isn't anything going wrong with them presently, my suggestion would be to wait and see what happens try not to baby them too much....that's the real killer.
If you are using water from the tap, make sure you are using only cold as here are less salts in it, but ya you should definitely use plain water for the rest of the grow...Maybe try reducing the heat as well (raise the light).
I do 10/14 right off the bat after a 16/8 Veg, and they don't finish any faster, but they do get frostier in my opinion. Also, if you are growing a purple strain it gives more darkness and more opportunity for cooler temps at night which can lead to more brilliant colors.
If you FIM them it looks like they may get wider which is going to make for a pain in the ass when you try and get in there to water them. Just experiment...Either way they look good and you're going to get some bud.
I'm doing both right now at the same time, and I have to admit, Hydro is a bit faster (i'm using a dwc...probably the cheapest way) than soil by about 1 week or so. The only down side is the hydro requires way more attention than soil. I've made really cheap hydro setups using anything from...