The delayed release of the 5.5 is the most interesting/curious rumor.
These are basically competing devices and in the current market of wanting/needing to brag about first weekend, week, month sales, theres no doubt sales of the 4.7 would take a hit.
It *is* interesting, but this might actually be a good thing. Apple can keep the hype at a feverish pace by having two release dates. All the people who want the smaller one will get it first, but there'll be a whole host of people who want the bigger one that will wait, and they will be their own class of people bragging about firsts. There'll be the late September wave of people doing the wait, the receive and joy round, and then there'll be *another* round soon thereafter. Apple would dominate the tech chatter from now into next year between two iPhones, new iPads, Yosemite and (please god) new iMacs.
I very much doubt 4.7" models would take a hit. The secret is to upset the people who want a 5.5", but not *too* much, and then deliver a device that will make at least those who waited think they wait was worth it. Perhaps the screen would be enough, or perhaps the 5.5" really will have some small features the 4.7" does not.