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.
you could leave the DHCP on for one that you would like to be the default
and assign the ip's/domain ect.. to the other with its DHCP turned off
or get another switch to seperate the networks, but it would make file/printer sharing more difficult
since your WRT54Gx is using dd-wrt firmware you cannot use a WAP54G with linksys firmware as a repeater
it is possible to flash your WAP54G with the micro ver of the dd-wrt firmware, then set it up as a reapeater tho