It´s not possible to unlock aura or semblances with dev tools ;)

The Aura unlock is a storyteller event like drop pods etc. but can only happen if a pawn is wounded (bleeding or not doesn´t matter)

For unlocking a Semblance a pawn needs to have an Aura already.
Then there are 2 ways of unlocking it.
The first is also a storyteller event like drop pods but can only happen if the pawn has certain really strong emotions, like family member died etc.
The second way is if a pawn with an Aura does certain things or certain things happen like getting hit by lightning or killing a certain type of enemy but this has a chance and is not guaranteed to unlock the Semblance. These things are thematically near the anime or what the Semblance specializes on.

Edit: If you want more details, that would be HUGE spoilers xD

Have you hard-coded in an upper limit regarding the traits? So, say, if I had a pawn that already had 3 or more traits would that block them being able to attain either the Aura or a Semblance?

And as long as the HUGE spoilers are covered with a tag, I suppose it wouldn't hurt to have the info down for anyone curious enough to look :P

Nope, there is no limit in traits.

And here is the HUGE spoiler how to unlock the Semblances without storyteller event:
Ruby: deal damage to humanlike pawns (any amount), 0.5% chance, lower chance the lower the damage dealt is
Yang: take damage (any amount), 0.5% chance, lower chance the lower the damage taken is
Blake: flee, 5% chance
Weiss: kill a grimm, 2% chance
Nora: get hit by vanilla lightning, 100% chance because it´s so rare, get hit by something that the Semblance normally would absorb, 1% chance
Ren: get raided by Grimm, 20% chance
Jaune: tend to other pawn, 2% chance
Qrow: get your surgery failed, 10% chance
Pyrrha: down or kill a mechanoid, 2% chance
Cinder: get set on fire, 5% chance
Hazel: get downed because of pain, 3% chance
Raven: pawn you like at least with +50 gets downed, 10% chance
Velvet: do a social interaction with another humanlike, 1% chance

The chances are not final and may get changed if i see (or get feedback) that certain things are too rare or common.
Also as you can see, this can all happen naturally and if you have alot of pawns with the Aura trait, the Semblance unlocks should happen quite often. Also keep in mind, that more Semblances will come, which will increase the rate of pawns unlocking Semblances.

EDIT: updated the spoilers

That is awesome! Have you increased the chances of lightning hitting a pawn at all I've had that happen a few times now and it never ceases to amaze me.

Also, what are the chances of a pawn getting an aura when injured? and Does any injury count, even if it's a minor one like a bruise from a social fight?

Nope, i haven´t increased the chances but if a pawn already has the Nora Semblance, lightning that would hit in a radius of 10 around the pawn will hit the pawn instead.

The chance for Aura unlock event is a bit lower than refugee crash pod, maybe it´s too low, i am waiting for feedback, see the Balancing part in the mod description and yes, every injury that is tendable counts

So, I've done a bit of playing around.

It's possible to Give colonists their Aura with Dev Tools (using the give trait command).

I didn't try and Give the Semblance straight away, but now my guy has Rubys'. I removed the Semblance Ruby trait and he still has the abilities. Is there any way to revert him back to normal so I can test another semblance?

Right now there is no way to take away the abilities as i didn´t think of giving trait with dev tools

This MOD can take away the abilities. but Kills the host.
https://ludeon.com/forums/index.php?topic=48062.0

Having played around you can remove the powers. But it requires messing with the save files. In essence you need to find the part where the aura of the pawn is defined and change it to the aura of a normal aura-pawn. To allow for semblance unlock you also need to remove the semblance trait and add the aura trait (although the traits don't seem to play a role in actually having the powers). In an editor like vs code (or any with search functionality) search for ruby and go to the last occurrences, those are most likely the pawn related ones. You also need to find an example of a normal aura, ctrl C ctrl V.

Also, may i suggest making the chance of unlocking aura proportional to the severity of the damage taken. Pushing the pawn closer to death would exert them more, meaning more likely to unlock their aura in pure desperation

Don't worry guys, i will make it so that if the trait is gone, the abilities disappear too. Because sooner or later i need to implement this anyways, because i planned to add the Aura steal bug that Cinder used on Amber

I never saw that much spoils lines in a single thread page Cx

Going with what @Areskiko said last regarding the chances to unlock semblances and auras Would it be worth adding in an ability for a pawn with a semblance to unlock the aura of another pawn like Pyrrah did with Jaune? Maybe have a long cool down on this ability for balancing issues[/spoilers]

@UnhandsTool
Pyrrha´s Semblance already has that effect

You shoud add the unlock Aura on the other Semblances.