Convenient summary h/t Ivan Vladimirov.
Ireland and Iceland look to be in the best shape. While Ireland is one of Europe’s most religious countries, Iceland is one of the least (“0% of Icelanders aged 25 or younger believe world was created by God“).
Adjusting for fertility non-EU immigrants also substantially smooths – indeed, probably almost removes – the TFR differential between Western and Eastern Europe.
Note also that in countries with a long history of immigration, such as France, there will be a still small but rapidly growing – and presumably, still higher TFR than average – demographic of non-EU ancestry that are now getting counted as “native.”
How could Russia fare in this picture? Its TFR reached a local peak of 1.78 children per woman in 2015, the year of the above survey – that’s equivalent to the native rate in France and Sweden, the two highest TFR countries other than Ireland and Iceland. Its main group of non-natives are Central Asians, who don’t appear to be reproducing much within Russia itself (since immigration tends to be temporary and dominated by males), so they wouldn’t change the figures much.
However, certain small ethnic minority groups are substantially more fertile (primarily, Chechens, Tuvans, Ingush, Dagestanis) and will make a discernible if modest statistical difference. Based on census results, there is good reason to believe that the difference between ethnic Russian and total Russian TFR is around 0.08 children per woman, so ethnic Russian TFR would have been around 1.70 in 2015 – almost exactly the same as in Latvia and Lithuania.