All biopotential recordings can suffer from 50/60Hz interference. The largest contributors to problems are mains ground wiring and florescent fixtures.
For lighting we would recommend incandescent fixtures, perhaps low voltage (non-switching) halogen. For a very low power alternative, LED lighting would be an excellent choice, so long as AC/DC conversion elements are not introduced into the environment of the room. Its best to keep all switching elements associated with lighting out of the room. Fluorescents are not recommended due to high frequency EMI.
The electrical mains grounding should be as good as possible. This would imply using low gauge wiring (beefy wire) on all outlet ground connections and run each outlet solidly to mains ground at the sub-distribution panel.
It would be best not to daisy chain the electrical outlets in the room. It would be best if each outlet had a line which ran back directly to the sub panel breaker, In this manner the sub-panel would act as the common distribution point for all power issued to the room.
This electrical design is very helpful when the room is used in practice. For example, if some equipment is brought into the room which generates mains conducted EMI, this potential EMI will be very well isolated from other room outlets.