swears Well in the walkthrough unless I am missing something only the following is said about the divine shards.
Offer Wendis, Vhala and Aka a shard (they will refuse)
Give Uyae, Nalili, and Carina a shard
(Optional) Give the rest of the divine shards to whomever you'd like
So only Uyae, Nalili and Carina are recommended to get a shard and the rest are do as you like. From my understanding Altina, Carina, Lynine, Neranda and Uyae all give a small bonus during the final battle by having a shard and Uyae can also get some bonus XP she also get's a special item from her request that also factors in when counting how big a boost she gives during the final battle during the calculations. Trin get's a +1 trust bonus during, it's not really needed with the walkthrough. For everyone else the divine shard just gives a flat +5/10RP bonus and some additional dialogues for some characters and might have some more effects in post game most likely if you didn't unlock the final optional harem member.
Again though the boosts during the final battle is minimal and I haven't really gotten to the final battle part so again unsure if it actually affects anything I am guessing there isn't a mention since you can still get the best outcome even without them.