Google Calendar and Contacts would be the obvious choice and it's pretty streamlined since their sync works really well. I am in the same situation (WIN10 desktop and Android phones) and utilize the web-based Google Calendar daily. Any update made on desktop appears on the phones (including shared calendar to my wife) instantly with no need to manually push/pull - and vice versa if you update through the phone. On the phone, employ the Calendar widget and it's super practical on a daily basis.
You can also integrate Google Keep for a sync'd to-do list. Not sure how flexible/fancy MS's calendar is, but my suggestion is to get off MS and get onboard with Google. Through Gmail, your MS email can also be automatically forwarded there, as I do that with my Hotmail. It can still send out as the MS address if you need to stay on that email box.