Out of the brokers you listed, I have experience with IC and they seemed to be offering the tightest of spreads for Australian spot brokers, but in my experience and opinion tight spreads are simply a sales pitch and will vary at any time, the same goes for when you are profitable.
It is a shame as IC seemed to change some practices around Dec 2014 and started questioning withdrawals also.
A somewhat basic guide, is to view http://www.myfxbook.com/forex-broker-volume and the brokers allowing profits on http://www.myfxbook.com/community/trading-systems/4,1 live EA's only obviously. I find this a little useful. Regardless of what platform you use or system, it would appear to be mostly impartial (for now).
Scalping I wouldn't use any spot broker system but go straight to futures ex ladder only. But that's my opinion.