Ah, l now better understand your perspective on Chaos Cultists, it's just a common conception that Alpha Legion players have cultists troop because inciting heretical thoughts and behaviours in the human masses is one of their primary unique specialities. But l think your list will perform good without them.
Against deep striking units, if you want to spread out across your deployment zones, a good tactic is to have units no more than 18 inches apart from one another. As the opponent still cannot deep strike in between them, you can even leave a bigger gap against larger deep striking units, as any models that cannot be deployed at least 9 inches away from ALL enemy units will be destroyed. The drawback here is the extra distance you've opened up to shoot and charge those Crisis Battlesuits and what nots with the majority of your army.
The legion trait of -1 to hit rolls beyond 12 inches is wonderful, many units for Tau players are hitting on 5+ even when hiding in plain sight. Come to think of it, Ork Boyz can't shoot you with their shootaz after advancing while being 12 inches because of their base 5+ BS. While supercharging plasma guns self-inflict mortal wounds on ones and twos, Hahahaha.
With regards to ANVIL industries, their models sizes are really similar to GW and FW, they use the same base dimensions however they don't really have the heroic sizing with GW so they appear slightly skinnier up close. There are many reviews of their products on YouTube. I think the majority of their catalogue are better suited towards Imperial Guard and Renegades and Heretics armies, they do have parts appropriate for Chaos Space Marines, but the options are more limited compared to the regiment sections. Nonetheless, great kit bashing potential though.
For playing with strangers and other avid tabletop gamers, l expect it to be rare to find someone just waiting in a game store for someone to play against. You should definitely get connected with your local Wargaming community, some have their own social media pages while others use apps likes GameFor made by Uncle Adam from the YouTube channel Tabletop Minions (his video content is helpful to newcomers and humorous to veterans, P.S. he's not actually an Uncle
) to organise matches. I actually managed to find some nearby players this way but don't be surprised if some travelling is involved, but at least this way you'd want the game to last longer to make the most of it.