Hi,
1) Yes I can confirm that it is not possible for an non-EU citizen to transfer rights from other countries to the danish A-kasse system. Read more here: https://www.a-kasser.dk/transfering-periods-of-work-and-insurance-from-another-eea-country/
2) No, you need to meet the residence requirement. As an non-EU citizen you can only count the years you have stayed in Denmark. Only EU-citizens have right to (according to the EU-law principles) count stays in other EU-countries also.
So if you apply for benefits in 2019 you must have stayed in Denmark for at least 5 out of the last 12 years before being eligible for Unemployment benefits ("dagpenge"). This requirement will be 6 out of the last 12 years in 2020, and 7 out of the last 12 years from 2021.
So I would recommend NOT jo become member of an A-kasse now...it will be waist of money. Wait until you have stayed here around 6 years.
Best regards,
Anders Weber, www.a-kasser.dk