A:AnswerDepends on how tight your performance is. I haven't experienced loose performance with a wireless mouse or keyboard. There might be a slight input lag but I doubt you will notice the difference.
A:AnswerYes. I added one of those to mine. Only caveat is that the motherboard has location and standoff for it but no screw to secure it. After looking at some old devices, I took a screw from an old laptop that seems to be doing the job.
A:AnswerYou definitely could. Everything is accessible. I added an SSD and an extra HDD and reorganized the cables. I find the case to be perfect for what the system is, but if you wanted to use another case, there’s no reason why you couldn‘t.
A:AnswerI think the card is made by AMD as that is what is on the circuit board but I may be wrong and yes you can add another 16gb stick it is a dual ch.