1: What is "other way", relic slots are granted by temples which Kongo cannot build. Also, Kongo cannot ensure relic*3 belief(since maybe nobody choose it), which makes these relics actually worthwhile.
2: Suiciding is not that easy since apostles of the same religion cannot fight with each other, making this operation for Kongo tough. You may find yourself being able to suicide only after wandering around for 15 Turns, then you get the relic right when or even after the game ends.
Mention: It is well-tested that dying militaristically does not count.
You cannot persuade anyone only by saying easy words. Mt. St. Michel just don't quite work for Kongo.
IF using Yerevan what I actually values is the ability to transform Barbarians. If you can get 3 Musketmans from a Mbanza, you actually profit a lot.