However, it's highly likely that Microsoft will have a payment system. They already have documents up about how developers can implement their own custom payment method as well.
Yes but who knows if it will launch with the 950 or some update later this year. my guess is that staying true to who Microsoft is, it will launch next year 2016. Once again being late to the party. And not fashionably late either.
Here is the demo Microsoft showed at a conference in Asia earlier this year. https://www.youtube.com/watch?v=lUwie6HFHjs or search windows hce on youtube
If you have a secure SIM when you view the NFC payment settings it will appear as the default payment card. I haven't tried to use it yet but let's hope they are moving in the right direction.