I can't imagine Palace coming into town on a Friday night is something the police would relish to be honest. With a much busier night on the trains anyway with many people on a night out in town, think they'd be better off keeping it to the Saturday. Sunday surely the main alternative.
I've never had a problem locking my bike in the racks both covered and covered just down from the old bandstand area. If 1000s more turn up on bikes, then it may well be a case of find a railing or post where you can.
Hove and Lewes Stations to the Amex are actually only a 5 mile walk, Portslade Station is 6.5 mile walk. I've done that as a Sunday stroll with young kids and family in tow. Set out at noon, couple of refreshment stops along the way, don't be in too much of a rush after. As a one off at least...
Do enjoy arriving for a match on a bike, gives you a nice spring in the step.
To all fans really, from anywhere along the seafront, from the Palace Pier up to The Level, it's pretty flat all the way to the Amex with safe cycle lanes pretty much for the entire journey. If you don't have a bike...