glojo,
I can't say that your pictures look very much like the IPP as I remember it, but I could be wrong.
The heat from the IPP exhaust was all terribly exciting a year or so ago, and legions of aviation press reporters and rumour website posters were citing it as the end of the world and a reason to cancel the Program. Turns out that in this (as in most cases) they were utterly wrong. The IPP can operate in 3 modes - bleed mode when it's being spun by bleed air taken off the main engine, burn mode when it's operating similar to a good old-fashioned APU, or bleed-and-burn which is obviously a combination of the first 2. Clearly the exhaust in bleed mode isn't hot enough to worry anyone, it's the other 2 modes that caused concern. These concerns were only relevant to a -B model because the exhaust vents downwards in a -B (shorter exhaust pipework = saved weight) and straight up for an -A or a -C.
In current flight test, IPP management is a total non-issue. When we first started flying the jet we were slightly concerned about stopping on asphalt in bleed-and-burn mode for any length of time - because the testing hadn't been done to assure us that everything was going to be ok. So there's a switch in the cockpit that the pilot can use to force the IPP into bleed mode whenever he has to hold on asphalt. LM are working on a number of minor tweaks to the design (including possibly making the exhaust come out at a more acute angle to the ground) and at an opportune point in the test program the team will take the time to figure out if the effects on asphalt are in line with the worst case predictions, or if they've been over-egged (which the safety folks have a habit of doing).
Any possible issues with ship integration will be thoroughly flushed out on the first deployment to USS Wasp later this year. Anyone who's telling you otherwise is living in the world of the ppt warrior.
Regards,
Single Seat, Single Engine, The Only Way To Fly