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.
I already have a good wireless router but I'm going to be getting Vonage.
Is it cool to just connect a regular wired router with a VOIP connector to one of my wireless router's wired ports? Will there be any issues involved security-wise?
The scenario you mentioned is probably the best way to do it. Vonage's "routers" are notoriously poor at routing. I have mine in the following configuration:
All of my PCs and such connect to the 871. I do not have any ports opened on the Cisco 871 for the Vonage, it just works. The Vonage "WAN" port is what I have connected to the 871.