Sorry if my title is vague or poor, but I'm very, very new to making datapacks for origins, and i got a little bit of it down. The custom origins do appear in game, but their custom powers aren't showing/working. Am I doing something wrong? I followed the CandyCaneCazoo tutorial but it still didn't work.

This seems like your problem actually. I don't know if you already did, but I'd recommend going to the official Discord server for help on doing Datapacks.

These are the powers themselves

{
"type": "origins:fire_projectile",
"entity_type": "minecraft:fire_charge",
"cooldown": 3,
"hud_render": {
"should_render": true
}
{
"sound":"minecraft":"item.firecharge.use"
}
}

And

{
"type": "origins:conditioned_attribute",
"modifier": {
"attribute": "generic.attack_speed",
"operation": "addition",
"value": 9,
"name": "A boost of strength under a primary curse influence."
},
"tick_rate": 20,
"condition": {
"type": "origins:in_rain"
}
}