If you get the 61.75 "based on" FAA private there are two paths to an I/R. If you hold a foreign I/R and pass the Instrument Foreign Pilot written test before you you go to the FAA office to have your private issued you will be granted a private certificate with an I/R. That certificate is only valid if the foreign license is valid. To fly IFR in the states your EASA license would have to allow you to fly IFR in Europe.
Or you can do the paperwork shuffle, get the 61.75 certificate and then pass the regular I/R written test and regular I/R checkride. The examiner will then add the I/R to your 61.75 certificate with the note US TEST PASSED. If you were at some point to get a FAA commercial this I/R would transfer over to that certificate.