Returning to 40k, mechanised guard feedback

Hi everyone, I'm coming back to WH40K after a very long time, and I'm planning to start collecting an Astra Militarum army. I want to do a mechanised regiment with some recon units. I'm building a list mostly around the rule of cool and the units I want to kitbash and paint, but I was wondering if this list would still be viable in games.

Gaunt’s Ghosts (I’ll use half of the new Recon Squad to proxy them)

Cadian Command Squad, vanguard honors

Commander with power weapon and plasma pistol

2x plasma guns, voxcaster

Chimera: multilaser, heavy bolter, hunter-killer missile

2x Cadian Shock Troops (10)

Sergeant with autogun

1x plasma gun, 1x grenade launcher, voxcaster

2x Chimeras: multilaser, heavy bolter, hunter-killer missile

Tempestus Scions (10) (I’ll use Kasrkin proxies)

Tempestor with power weapon and plasma pistol

2x melta guns, voxcaster

(I'll use deep strike, so no chimera for them)

Ratlings (5) (I’ll use the rest of the Recon Squad here)

Hellhound

Inferno cannon, heavy flamer, hunter-killer missile

2x Scout Sentinels

Lascannon, hunter-killer missile

That makes 1000 points. I know the new edition will be here soon, so it might change, but just to have an idea.