After seeing the new luminary and imagining a character for myself as a 80s hairmetal synthwave rocker who shot lasers out of their guitar, I got inspired to make this archetype! It's definitely not finished, but I'd love folks' input!

Stardust Rocker Archetype (2)

• requirements: performance (trained), charisma +2
• you are a rocker in every corner of your soul, allowing you to use musical instruments in ways previously thought impossible, even to turn them into instruments of death. You gain proficiency with all weapons with the [Professional (Performance)] trait. 
• Wheelhouse: Pick a genre, weapon, and instrument to be your wheelhouse. You gain a +1 circumstance bonus to checks made when performing with any instrument or genre in your wheelhouse. The weapon selected must have the [Professional (Performance)]
• You treat the Singing Coil and any weapon that deals sonic damage as having the [Professional (Performance)] trait. If the singing coil is in your wheelhouse, you may change the damage type it deals to sonic damage as part of the Tune action.
• Weapons in your wheelhouse gain the tuning trait and you gain the Tune action. 
• Any weapon you wield in combat is considered your instrument for the purpose of Stardust Rocker feats.

Tune <1 action>

• You switch the tuning of your weapon, changing traits or other statistics according to the tuning you select.

It goes to 11 (4)

• You add [Boost] to the list of traits you can tune your instrument to. The damage die of the boost trait is equal to the damage die of the weapon being used.
• (AN: a lot of the sonic weapons do already have boost, so I've debated on making this an area cone instead and push the boost tuning to a later feat.)

Roadie (4)

• You are an expert at maintaining your kit and adding in new and unique tech. with 1 day of downtime, you can install the components of any weapon with the [Professional (Performance)] trait into an instrument that is in your wheelhouse. Your weapon and instrument now become one merged item with the external appearance of an instrument.
• You can make your kit your own. Instead of installing the components of an existing weapon into your instrument, You may upgrade your instrument to have the stats of a Sonic Rifle except it has a d8 damage die and is considered to be a martial weapon for the sake of proficiency.

Wild Thing (6)

• when making an area-fire, auto-fire, or boosted attack with an instrument in your wheelhouse, you may choose for it to deal fire damage instead of its original damage type. When you do, it is treated as being in the flame weapon group.

Ready to Rock (6)

• When wielding a weapon in your Wheelhouse that has the Area trait, you can make a standard attack with it instead of an area attack. If the weapon has a damage die of d10 or higher, this strike has a damage die of one size smaller.

{Tuning, cone//boost} (8)

• (still working on this, but I wanted to have multiple area type options as tunings)

{tuning, line} (10)

• (still working on this, but I wanted to have multiple area type options as tunings)

Evacuate the Dance Floor (12)

• requirements: Wild Thing
• Your expertise in setting the dance floor on fire has reached another level. You may now consider any weapon of the Laser weapon group as having the [Professional (Performance)] trait.

So I had the idea of building one of those imperial navy breachers or arbites from 40k with the shield and shotgun combo, likely as a guardian/soldier or soldier/guardian build. What I can't work out however is what the right way to homebrew either a 1h version of a shotgun(scattergun), a weapon trait, or a feat to enable the playstyle.

What Im thinking so far is either;

• a trait called "braced" or something like it where a scattergun (made martial because of the upgrade) could be used while holding a shield,
• a martial scattergun that is 1h but made into a martial weapon up from simple (ie sawed off etc)
• a feat where you can use the shotgun as 1 handed as long as you have a shield, and maybe if you dont move more than half of your movement (not including shot on the run possibly)