Pirrex, in a short answer, I would say that holding a frozen ATPL is not enough in order to apply. They are very specific in having the ATPL and also with the hours breakdown as informed by the agencies. From what I understand, even if you have a full ATPL - obtained on an airline, when upgrading - but has not the required hours (cross-country, PIC, night, etc) it will not be accepted.
What many people do is get the hours and check the ATPL via private flying, ie. renting a Cessna during the weekends and logging the hours.
I am sure others will complement my answer
Merry Christmas and good luck!
BF