preview on LAN address push the ...
It should pick up your new address.
Do you mean aTP-LINK range extender?
You can set static ip, I pretty much mirrored everthing from my router including the ip
and sharing same ip does cause havoc with my eset antivirus, so had to create an exception (shared ip)
If it worked before, is should work fine after. i cycle routers every couple months to a year with no issues. As long as your firewall allows ports 50000-50100 you are fine(you can choose your own range too).
I just set up ESET which took over my windows firewall. So ashleys tut is pretty good with stuff like that