Using netctl is the preferred way over NetworkManager for servers. The main reason is, that normal users should not be allowed to alter the network configuration in case of a server.
VLANs are used when you only have one Network adapter and want to use it for multiple ip networks at a time. A router with VLAN support is also needed. TCP-Packages get a special
Tag attached, which identifies the virtual interface they belong to. With netctl it is pretty simple to setup and examples can be found unter
Bridges are most useful in combination with virtual machines as they provide a way to give every virtual machine a didicted ip on the network, which make them appear as any other real computer from that perspective. The bridge itself can also use dhcp or static ip addresses but does not have to. In case the bridge does have an ip address the host of the bridge is reachable via that ip, but configuring the bridge without an ip can eventually protect the virtualization host by making it unreachable via network. A second network interface card or vlan can then be used to access the host by admistrators. Again examples can be found unter
/etc/netctl/examples and look like this:
Description="br0 with eth0"
In this example
IP=no is used where
IP=dhcp also works