The only reson I can think of to want integrated graphics is because you have 5 monitors and graphics cards generally only have 4 outputs, but if that’s not the case, you should be fine without. 5700x3d as another commentor said is decent, I would go look at the Gamer’s Nexus charts to compare models.
Ram should only be used with the sticks in the kit because they are binned so tight. If they’re off by a little bit, you’ll lose a lot of performace, so you want to upgrade to 32 GB, you’ll have to buy a 32 GB kit.
Sata drives need to be connected directly to the mobo, so if you want more storage, you’ll have to swap a drive with no empty sata ports, but looking up your mobo, I’m seeing at least 4 ports, 3 in the bottom right and one spaced a little higher, so do you have disc drives or something taking up the other 2 ports left from your hard disks?
If the dimms are in the correct slots, they should be in dual channel. I belive cpuz shows memory information. I did some more reading on mixing memory and I remembered things a little off. The rule of thumb to not mix kits only applies to if you’re going for peak performance, but otherwise if you match speeds and timings it should work fine but you’ll loose the top 0.5% of performance, which is margin of error. If you start mixing timings and speeds, it will all run at the lower speeds if it works,but you run the risk of incompatibility, which generally shouldn’t be a problem, but you could get unlucky, so taking that risk is entirely up to you.