Rite and Shards are a nice way to get even more value from the enchantments.
Knight and Rallier are value creatures to blink. Knight is decent with the counters deck. While I think the swap to Evolution Witness was a good one, the Astral deck might be missing an Eternal Witness effect as I think a way to recur cards from the GY is important for this deck. Rallier could be that card even if it's capped in what it can recur.
Not easy to find interesting cards for this. I'm not big on multicolored removal, but Captured plays well I've heard.
Kutzil is ok, but I notice you don't have many equipment/auras/anthems making it less versatile than it could be.
Kudo works well in White with tokens and counters, but less so in Green where most of your creatures are huge. So, probably not a great suggestion, but a funny one
