Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
Yes, you can use that motherboard in any ATX case, as long as the horizontal length of the CEB board (267mm vs 244mm) doesn't cause any fouling on other chassis elements. Mounting holes are the same between the two standards.
In other words - as long as your existing ATX case has 23mm between the right edge of the board, and anything else, you're golden. Be mindful of whether the extra 2cm will cover any cablerouting grommets though, or you might find cable management becoming a pain.