Sounds like it should be ok... although make sure the macbook has firewire. Some older models do... and if possible I would consider a macbookpro.
Latency depends on a number of factors, but while recording you can decrease the Buffer I/O Size (latency) and always increase it during the mixing stage.
Freezing tracks (bouncing to audio) is a very simple process in Logic and a pretty flexible procedure.
Some plugins are more processor intensive than others... again there are ways to decrease the negative impact this can have on your Mac.... increase the latency would work well as well as sharing effects... e.g. routing the signal from, let's say, multiple drum tracks to a single Reverb effect rather than having multiple reverbs on each drum track.
Basically there are many ways to make different systems work :)
I'm not familiar with the 1814, so couldn't recommend whether it will run well when plugged into a firewire hub. Might be worth asking M-Audio directly to see what they recommend... but many audio interfaces run fine either sharing a hub with a HD or plugged in to an external HD's spare firewire port.
Hope that helps some more!