as for the yellowing, i would add some K and N to the mix.
check the ph.
make sure temps dont reach above 86 F at any time.
it looks to me like the leaves in pic. 1 are reaching up to the light.
and if you dont already have one, i would buy a grow bible, they come in handy in diagnosing your plants.
:greenthumb:

they are looking great though!
hope something i said helps.
happy growing!