Yes... the FAA will recognize your experience.... just depends on how much relevent experience you have and how current you are.. As for your IR lapsing... depends on when it lapsed... last week, or in 1997 ? Best thing is to ask them... the FAA website is pretty extensive...
Converting from JAA ATPL is straightforward.. the FAA written (as has been noted here many times before) is a complete joke compared to the JAR which is pretty much the equivilent to a BA in aviation studies in the states... the oral however offsets this to some extent... depends on who you get as an examiner... the flight test however is (or was in my case anyway) considerably more demanding than the CAA which seperates the general flying test from the IR portion.. In the US it's all combined.. my log book shows mine as being 2hrs 40min... almost all of this was under the hood with 2 precision and 3 non-precision approaches all but one were single engine with a multitude of 'quirks' thrown in by the examiner... again it depends on who you get... mine was fair but wasn't going to cut me any slack.