The factory stock is quite good, comfortable, light, and integrates will with the frame, and locks closed with a frame cut already there.
If going suppressed, be sure to throw away the US marked roller block, and get the Euro 40 degree block (apparently GO will send it to you for free). Not a terrible idea to get a spare roller.
Factory charging handle know and bolt release are fine, don't F'with them. The HB buffer block is a good upgrade, as is their safety upgrade - get that, the stock safety is too small as is. And the HB small profile "break" is a great low profile upgrade, thoughaybe not relevant if plan is to run suppressed.
Go order at least 10 of the curved mags. And 1 20rnd mag for the bench. Discard all the straight 30s.
Sights are up to you. I run a red dot that includes drops, for shooting further. I find a 25 yd zero is close to a 100 yard zero, depending, and just use that. You can go closer, but the sight offset is so high that any distance other than the exact zero distance, (if say 15 yards), is going to be very jacked up anyway.
If the made one small enough, I'd be tempted to run a cowitness green laser on the inside of the hanguard, to be right next to BBL axis, but nobody makes an Mlok laser that small. Probably would hit your supressor anyway.