|Ok you mean a 2 in 1 router / switch as a pure router does not usually have any LAN (ethernet) ports(aprt from 1 or 2 to connect to a switch rather it's the switching capabilites in the router that supply the ports, maybe you call it all the same thing.|
Pet peeve of mine, calling a SOHO router a router. It's not a router. I could show you a 'real' router. What it is, is a switch with NAT, DHCP and a firewall added to it. But they've commononly been called a SOHO router and the name has stuck.....incorrect or not.
1) You could use a switch connected directly to your modem IF you have a static IP address from your ISP for each computer you want to connect. It's worth noting that static (normally considered 'business level accounts') are more expensive than DHCP ('consumer level accounts') and you pay for each extra IP address (pay through the teeth I might add). So unless you have a lot of extra $$$, I'd recommend the SOHO router and possibly an 8 port switch, depending on how many clients you wish to connect to the internet.
2) Yes, it's a Star with the SOHO router or switch (whatever device everybody is connecting to) as the center of that star
3) Not likely with a SOHO router. For that kind of flexibility you would have to be prepared to spend thousands and get a real router.