If I cast Replenish , and as a result of it resolving aura shards and nyx-fleece ram (or any other enchantment creature) both come into play from my graveyard simultaneously, will this trigger aura shards ?
Aura Shards's ability will trigger whenever "a creature enters the battlefield under your control", even if that creature (such as Nyx-Fleece Ram)—
enters at the same time as Aura Shards (C.R. 603.6a, 603.10), and
has card types other than creature (such as enchantment) (C.R. 300.2, 300.1).
In general, if more than one permanent enters the battlefield at once (such as with Replenish), "all permanents on the battlefield (including the newcomers) are checked for any enters-the-battlefield triggers", such as that found in Aura Shards, "that match the event" (C.R. 603.6a, 608.2c). See also this thread.
If I cast Replenish , and as a result of it resolving aura shards and nyx-fleece ram (or any other enchantment creature) both come into play from my graveyard simultaneously, will this trigger aura shards ?