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.
Electrically, yes. An AGP Pro slot can supply (a lot) more power than a regular AGP slot.
As for signalling, no. You can use a regular AGP card in an AGP Pro slot (i.e. an AGP version X card will work in an aGP Pro version X slot), but I don't think you can use an AGP Pro card in a regular AGP slot.
And no, using a normal card in a Pro slot won't absolve you of the need to use an external power connector: all those extra pins in the AGP Pro slot are the source of extra power, and normal cards don't connect to said holes.