Canoeing leaves, light burn and lower leaf problem

[Rusty Trichome]

... They could be root bound again I guess. Is transplanting now a bad idea? They have about 4-5 weeks left of flower (estimate). Is it ok to let them get root bound now or will it still affect yield and growth.

If care is taken, you can get away with transplanting if need be. Wait till your next watering (when the rootball is sorta dry) and slip her out of the pot to check the roots. Then, since you have it out that far...transplant. Don't 'excite' the roots, they'll know what to do from there. :thumbsup:
Expect a little stress and slowed growth followed by the likelyhood of minor stretch as she celebrates her new rootspace. Do you have enough headroom for a slightly taller lady?

When do roots slow down to concentrate on bud growth?

They don't. If roots stop working, the plant dies a slow death.

Are the bottom leave problems due to just being on the bottom and not really having an effect on the plant. Possibly just low light down there and old leaves moving on?

Could very well be. Could aslo be due to the inability to uptake enough nutrients, and is feeding herself from her reserves. Could be a combination of the two. Might need/want supplimental side-lighting since the CFL effective range is very limited. Are you using the WalMart 23w CFL's?