Gentlemen please, can we all just calm down.
AIUI, the situation is this.
1. The US is proceeding with both the F35B and F35C, although concerns are being raised about the flyaway prices of both and their availability "off-the-line". F35C is also currently having some developmental issues with its tailhook, for which design modifications are being developed, but their effectiveness will not be known until trialled. We don't know whether it works or not at this point in time.
2. The US is currently developing the EMALS (and EARS system for recovery). The demonstrator system is installed at Navy Lakehurst and has successfully shot a number of US aircraft, including the F35C. So far all appears to be well in terms of fitting the first production set (of 4) to USS Ford. The second production set (of 2) is coming to the UK. EMALS appears to work well at this point in time.
3. The £1Bn being bandied about for a UK EMALS is not to "redesign" the ship, it is a budgetary estimate produced quickly when the decision to go from B to C was made during SDSR. Specifically, the activities required are to integrate the EMALS system into the ships structure (an alignment / local strength issue) and into the ships electrical distribution grid (principally a power management, software control issue) and also supply the shipset(s), which will not be cheap. However, the actual costing work is (as far as I'm aware), not yet complete, so the £1Bn may be about right, too high or too low. Simply put, we don't know at this point in time.
4. Were F35B to fall victim to US cuts, there is no fallback. The UK (and Spain, Italy) would be permanently out of FW maritime air. In order to meet the UK requirement, the F35B also has to engage in some pretty unwholesome practices on recovery. If the F35C were to fall victim to cancellation, there are at least two fallback options. That makes going back to B a non-starter I'm afraid, when we know the risk appears to be primarily in the aircraft, rather than the ship.
5. The first ship with EMALS fit is unlikely to be available for ops until 2019-ish, so we have seven years before we have to rock up at the ship with an aircraft. In other words, it doesn't have to be sorted right this second! In the next year, no more than two, definitely. However, we do not have to make a decision (F35C or FA18/Rafale) at this point in time.
I don't think there's a man alive who thinks that the QEC/JCA saga is how one should go about procuring a carrier and its aircraft. However, one of the main sources of delay and cost escalation has been the endless speculation (often ill-informed) in MoD, industry, the Navy and the press. "It's too big (for which read expensive)/training burden/shipbuilding capacity/unsafe recoveries" have become a mantra over the years, constantly deflecting / deferring progress.
QEC build appears to be going very well (largely because folk have been left to get on with it) - there may be a lesson in that.......