Can I do it? Is it ok?
I’ve searched the threads database and didn’t find the answer, and we had a pretty heated discussion on whether Mirriri, Weatherlight Duelist will be saved.
Yes, this is allowed. Sigarda's Aid lets you cast Lightning Greaves in response to Arrester's Admonition, which means it will get to resolve before Arrester's Admonition (C.R. 116.7, 304.5, 116.1a, 702.8a). And once Lightning Greaves enters the battlefield under your control this way, Sigarda's Aid's second ability will trigger, will go on the stack above Arrester's Admonition (at which point you can target Mirri or another "creature you control"), and get to resolve before that spell (and to let you attach Lightning Greaves to the targeted creature to give it shroud, making that creature an illegal target of Arrester's Admonition) (C.R. 608.3, 116.3b, 116.5, 603.3d, 601.2c, 114.1a, 405.2, 116.4, 702.18a).
I have Mirriri, Weatherlight Duelist and Sigarda’s Aid on the battlefield and it’s combat phase, I want to attack my opponent with Mirriri, Weatherlight Duelist and declare so.
He casts Arrester’s Admonition wanting to return Mirriri, Weatherlight Duelist to my hand
I cast Lightning Greaves and want to attach them to Mirriri before Arrester’s Admonition resolves, and save my cat, both actions based on what Sigarda's Aid gives me
Can I do it? Is it ok?
I’ve searched the threads database and didn’t find the answer, and we had a pretty heated discussion on whether Mirriri, Weatherlight Duelist will be saved.