Turkey, Serbia, Republic of North Macedonia, Switzerland and now UK are all “Non-EEA countries”
There is a slightly different approval criteria in CEN and CENELEC. However, for both organizations the following apply from CEN/CENELEC Internal Regulation part 2
6.2.X.1 Votes from all members are counted first, and the proposal shall be adopted if the CEN/CENELEC approval criteria are fulfilled.
In case the proposal is not adopted in accordance with 6.2.X.1, the votes of the members from EEA countries shall be counted separately, applying the same approval criteria as in 6.2.X.1.
This basically means that only in the case of e.g. non-approval of standards, there will be a second counting, where the non-EEA countries votes are omitted. If a non-EEA country has voted no, and the proposal is approved in the second counting, the non-EEA country is not obliged to adopt the final standard.
"Which products should be UKCA marked after 31 Dec 2020? Is it only CE certified products that are included?"
The UKCA marking applies to the product groups that were previously subject to requirements for CE marking. In addition, UKCA marking also includes aerosols. Please note that several product groups that are covered by UKCA marking are also subject to special rules. This applies to Medical Equipment, Railway Interoperability, Construction Products and Civil Explosives. You can find more information here:
https://www.gov.uk/guidance/using-the-ukca-mark-from-1-january-2021