I dont think we can exactely anticipate the effect of the Q3 line up of the Switch.
It can still be : 2 - 3 - 12 - 3 for the 4 Q until 31th March 2019.
Wii's best ever Q3 shipment was 11.3m, Switch will not beat that this year.
Just checked and the DS never got to 12m shipments in Q3 either, reached about 11.7m. 12m is unheard of. 10m is probably an optimistic estimate for Q3 switch shipments this year
LTD: PS4 - 125m, Switch - 110m, XBO - 51m
2020: PS4 - 9m, Switch - 22.5m, XBO - 2.5m, PS5 - 4.5m, XBX - 2.8m