The fact Engage is on the RB rotation means that it's possible to have Tokyo Mirage Sessions AND Engage as the bonus games. This is a tiny selection of 18 units, of which only 3 are grail units with only two more in the 3-4* pool. With three more units as rearmed or seasonal only, this greatly restricts the commonly available units. Additionally, such a combination would have zero bonus heroes.
A full F2P score demotes this week on Interval 20.