I am not from America, so excuse me if I overlooked any of your state laws.
>upper and lower receivers
smart shopping. rock the proletariat pony. to account for the the off-chance something is drilled or milled out of spec, make sure you are guaranteed good customer support after purchase. I haven't communicated with Anderson at all, but I imagine their warranty is decent, being a sizable company with very high volume production.
stainless is fine - get the most affordable tube and never pay extra for nitriding unless you like black. tubes made of superalloys are an even greater waste of money
should be fine - all the usual points are addressed. I think with the expanse of internet reports and the fact that Battlefield Las Vegas uses them a lot inspires confidence. I like BCM or Colt BCGs for that ultimate piece of mind, but I admit it's just a spook I can't get over.
oh god no - I own of these and I can't even sell it to anyone out of principle. that latchless design WILL eventually fail and you will be bonked in the nose. just get a USGI charging handle, or one of the Gen1 BCM medium latch charging handles if you want comfy
should be fine, same "concerns" as I have for the BCG. remember to coat everything in a thin film of lube before installing
I am really unsure what you are trying to do with this - a 24" stainless steel bull barrel is kind of the opposite of handy and practical. If you really want that rifle length gas system, go for an 18" or 20" barrel. I really do not recommend stainless steel unless you have plans on making this a precision rig. I like Green Mountain Barrels if I want a quality, very affordable milspec barrel. BCM and Daniel Defense are g2g as usual. There's so many barrel makers with varying quality that it's hard for me to give a pinpoint answer here. I can definitely talk more about match grade stainless steel barrels if that is indeed what you wanted (just buy Krieger).
frankly I don't trust it and a quality rail is not too much nowadays. BCM MCMR is my go-to because I hate "clamp-on" systems and it's fairly affordable. Any variant of the Zev Wedgelock rail is also great and offers a more secure lock-up with the barrel nut, but it is more money.
I am not familiar with the dirty bird receiver set, but it seems to check all the boxes. the clamp-on system can be overlooked at that price.
let me know if you have any questions, or need help with your optics selection. I probably know more about that than anything AR.