It is highly doubtful that apple will release another portable device to to canabalise the IPhone and MBA sales....
If they release IPhone in MAY it is very likely most of the customers will hold on to there money to wait an see what is going to happen at WWDC....
As of now.... if they release only the gen2 IPhone hardware in May then the full potential of the IPhone gen2 wont be realised untill WWDC when they will release the IPhone ver2 software.... which will bring in the extra features... which Apple will be willing to show off.... and more specifically at WWDC because they will have the executive crowd whom they intend to please with this version.....
If they release the new device in WWDC then it will eat into the sales from the customers who will b waiting and watching.... Since most of the Mac loyal customers already have an IPhone.... they will decide not to upgrade to the new IPhone and rather opt for the new portable device to have a go.....
M sure this is not the direction apple is going to take.... SJ is a very vice chap.... M sure he wont like the new baby canabalising the sales of the IPhone....
Sorry to disappoint you but I would say Apple would have enough of gen-1 IPhones even if you ship yours after WWDC to give you an replacement. If Apple has EOL the current version then they would still have some stock remaining. On the other hand they would still have some refurbished stocks at that time for you.... So m pretty sure they wont give you a free upgrade to Iphone gen2.... they will rather want you to buy one....
Most customers wont even know (nor care) what WWDC is. Remember us lot here are far from representative of the total Apple iPhone customer base