First and foremost, I am a complete n00b. I have only been exploring lore for a few years. I was always intimidated by the table top game but now with the Cavil movies/series coming I decided to make the jump. I heard that Knights might be a good army for beginners. I kind of like the lore and love the miniatures. Before spending too much money I picked up the Knights Codex.

My question comes down to painting and gameplay.

It seems like the game allows you a bunch of flexibility to customize your faction. You can either just align with one faction with its strengths and lore and stick with it paint and all, or you can create a custom faction. It also seems like there is a bunch of flexibility within to basically pick from a wide variety of martial traditions, strategems, warlord traits and relics. For example, even if I'm freeblade under certain conditions I can align that freeblade faction as questor imperialis or questor mech and get those questor specific modifiers.

I guess my question, it seems a person can just paint whatever color they want, and when it comes to the individual games just say whatever you want to align your Knights with to get the strategies best suited to the army you are about to face. Like I can paint my Knights purple, come in and say they are freeblades one week, then the next week say they are questor mech. Would people look down on that? Can I paint my Knights as an AdMech aligned questor for house Taranis, and when it comes to the game align my units with a different admech house or say "oh these are freeblades/imperial." Would that get a side eye?

Finally, in tournament play (long way away from that) are you expected to keep your specific alignment the whole tournament. I'm assuming I'd have to play Knights, but would I be allowed to switch Questor, House, and other strategies from game to game?

TL/DR Can I just paint my knights any color and switch the questor, house, and all that stuff from game to game regardless of what markings are on there?