@protoaddict of course, they need to be instant or else the whole cycle fails. My bad. Yeah, instant Hymn is of course not viable. Thing is if the black one is removal, the red one can be just that too - but maybe they'll settle for a new "Fireblast".
My guess is that red will be a pyroclasm style effect as that is a turn 0 answer to tokens, White may be a pitch angels grace style cant lose effect, and black will be some snuff out style thing or a resurrect effect.
It is in reds color pie to get a non-basic land destruction spell but as a free card it would probably ruin modern at free and instant speed. You could also see a prismatic strands style card or grave hate in white but those feel too weak.