Nice looking plant and it looks to be well on its way to producing a decent crop of buds.
Yes, a photo showing the whole plant from top to bottom so we can have a better chance of seeing what you are noticing when you look at the plant. Sometimes when the very lower leaves start to turn brown and die off it might be because of lack of sufficient light below the heavy canopy growth.
Yes, this. Often a leaf that is turning yellow for awhile before starting to turn brown is not as big of a deal as a leaf that starts off turning brown. Sometimes those leaves will fall off just by touching them and no need to give them a tug.
Yep, it would really help if a photo of the whole plant is posted.