"Thank you for your response! Is there an FAA email that i can contact and confirm these details with?"
Any FAA inspector familiar with Part 61 will tell you the same thing that rudestuff wrote. You can also speak with someone at the Airman Certification Branch in Oklahoma City for assurance.
To echo the other replies here, your UK CAA licence is irrelevant to the extent that you can rip it up and continue using your MEA ATPL.
"Would I be able to use the ICAO ATPL to convert it to an FAA ATP..."
Only a Canadian ATPL can be converted to an FAA one. In every other case, you must meet the FAA training and testing requirements as set out in 14 CFR 61. You can credit foreign flight (but not sim) training under 14 CFR 61.41. If you want anything other than an ASEL rating, you'll need to complete an FAA ATP-CTP.