It seems you are making it complicated. If you are getting the type-rating now, just do it at an EASA approved facility and you are done. What you are talking about REALLY, means that you have to get a FAA license, do the type-rating, do your 500 hours and then yes, you can put the TR on the EASA certificate.
But getting your full FAA certificate and the TR is going to take you as much time and money as an EASA TR. So you seem to be creating your own dilemma.
If you are thinking that you can get a non-EASA type rating, without having a FAA license to "stick it on," and somehow combining a non-EASA type rating with an EASA certificate and fly on that, the simple answer is no you cannot. A type rating is applied to a certificate and if you don't have a FAA certificate, then you don't have a TR.