I feel we can proceed in the way syfa, you will let her free in the church and then can join with her again in the main church and then you can betray her and trap her with mirror. As the choice for anya was very early i feel people should another choice where he can betray them or continue with them.
And each of these backup routes reduce th importance of choice, which is also a thing people talk about and contest.
How to place such choices strategically and still maintain the importance of choice has been an ongoing learning experience for Chyos... one of his solutions was to trigger a save before an important choice and as far as I recall the Hekima support or oppose choice was such a choice.
Also Hekima support leads to NTR, while oppose to the love route of Anya, the backup choices concentrate on that most of the time.
For Mira the only chance for a Harem route is to refuse Syfa in the sanctuary so the 2nd choice is removed from Miras path, yet decides wether you want to corrupt, NTR or Love the other girls in the church.
The betraying her with the Mirror choice is probably to initiate the corruption path with the other girls while NOT engageing in the NTR path that would follow by sabotageing the ritual... so it's not really a backup choice but rather on how to proceed with the girls in the church (like giving Liandra to Giron but giving her a chastity belt).
Again I don't have practical experience with the NTR path since I avoid those.
I checked the wt but didn't saw any john and mellisa content. The only NTR I saw in wt was crow goons
I remeber it was mentioned before... something about after John comes clear about Melissa not being his daugther and if her corruption is high enough and she had sex with the goons she'll have a secret relationship with John.
But again no practical experience so the triggers might be different, it wasn't just idle talk about possibilities in the future though