t400cn getting replaced by bw400cn soon, somewhere this month.
t400cn is design to develop in c41 and printed on bw paper, if u print on colour paper u get a little sepia, if the lab is beri eng, they can adjust it so it will not look so sepia.
the upcoming bw400cn is design to develop in c41 and printed on colour paper without much compensation from the lab. dunno it will fare against t400cn.
tmax100 is a true bw film, it needs the tmax developer which is only available in a few places, ruby charges like $9 to develop and do a contact print, quite expensive compared to t400cn.