First, the new iPhone will be 4G LTE compatible. That shouldn't come as a surprise to anyone, considering the new iPad supports LTE and it's hard to imagine Apple giving the iPad a feature like that and not passing it on to the iPhone. So look for that this fall.
Second is the timeframe. We've mentioned October 2012 as the current release schedule for iPhone 5,1 before and it sounds like that's still the plan. The exact date almost certainly won't be determined until it gets closer to launch, but the iPhone sounds locked to a fall cycle for the immediate future.
A new micro-dock connector would give Apple more space inside the device as would the new nano-SIM. That space could be used for more battery or to make the device smaller/thinner.
Apple's timetable for the release of the new iPhone will likely be revealed based on whether iOS 6 is unveiled before or during WWDC. If it's unveiled at WWDC a fall release of the iPhone would be likely.