The original reason Regen I and II where added earlier was so they could be subbed. Now that it doesn't matter, expect normal priorities to apply (That is, specialist roles getting spells before/exclusively). Since the .dat's don't point out at SCH getting Regen IV, I wouldn't count on it.
Besides, Addle is likely going to be Regain: Which is probably more useful and also more fitting into SCH's lore.
It is better wither to be silent, or to say things of more value than silence. Sooner throw a pearl at hazard than an idle or useless word; and do not say a little in many words, but a great deal in a few.