Need help using preset avatars from the Meta Avatars SDK

Device: Quest 3

I have to run an experiment for my project that requires me to assign a participant an avatar from a list of avatars. Once the participant selects an avatar from the list, the full body avatar should appear in front of them from a third-person perspective (3PP), and they should also be able to see the avatar's hands superimposed on their own (1PP, this is important). Both the 3PP and 1PP avatars should mimic the user's hand and head movements.

So far, the existing MirrorScene is working for me with Passthrough and a Grab cube interaction. 

https://developers.meta.com/horizon/documentation/unity/meta-avatars-samples#mirror-scene . I can see the avatar in 1PP and 3PP. I need to know how I can swap out this avatar for another. I believe the current avatar is a fallback avatar.

MirrorScene with Passthrough

NOTE: I want to use the existing presets available for Quest. There are 33 preset avatars labelled as 0_quest, 1_quest...32_quest. I will only be using a handful of avatars from these presets. I am NOT using avatars from users' Meta profiles.

P.S: I gave Mixamo a shot, but it's kinda time-consuming to make each joint work as I want, and making the Meta XR Interaction SDK work with Mixamo models is a pain.

TLDR: I want to swap the avatar in the MirrorScene with other presets available locally. How do I do it? First-person perspective (1PP) avatar is crucial. I can't find many resources to guide me with this. https://developers.meta.com/horizon/documentation/unity/meta-avatars-overview

Just FYI, I am familiar with coding but have limited knowledge of Unity and Quest.