I don't see any reason they wouldn't work in those lights, but I don't know anything about the Milky light, he's made a lot of neat creations over the years, but I haven't really kept up with all of them
The M60 will have better runtime on the 3.7V style cells. But the ones you have will be fine for now. Just keep in mind that the 900mAH label capacity is pretty inflated, expect maybe around 500mAH give or take.
if you do buy 3.7V cells in the future, make sure not to use the charger that came with your 3.0V cells on them. It will overcharge 3.7V cells and increase the risk of fire/explosion/premature cell failure etc.
Eric