I just had to deal with this myself with my conversion. From what I can gather the English Language Proficiency must be done by an EASA approved English assessor. They do not accept ELP endorsements from ICAO. But any EASA assessor will work regardless of country. The Irish accept a Danish ELP assessment and vice-versa.
As for the radio licence, it varies between countries. The UK requires a new radio licence, as does Denmark. Although one former Danish CAA employee told me the ATPL can be issued without the radio licence, but you need the radio licence to exercise the ATPL privileges. Clear as mud? The Irish, however, do not have a separate radio licence - "Radiotelephony privileges are included within IAA pilot licences, rather than being issued as a separate document. There are no additional technical requirements to be met – you will be assessed on use of RT during the ATPL skill test." So check with the country you will be making the ATPL application with as the radio licences are different for each country. The UK and Denmark for sure require a new licence, Ireland for sure does not.
Hope that helps.