How to turn on the hotspot remotely (e.g. bluetooth)?
Yes, you can turn on the hotspot from the MacBook by choosing the phone in the WiFi menu, where it is displayed with a special icon. The feature is called "Instant Hotspot" and is accomplished using Bluetooth.


sign in to iCloud on both devices
Enable continuity (a.k.a. Handoff) on both - https://support.apple.com/en-us/HT204681
Enable wifi and Bluetooth on both macOS and iOS 


This requires you to be using the same AppleID on the phone as on the MacBook. You'll also need at least iOS 8.1 on the phone and OS X Yosemite or later on the MacBook.

If you open System Report on your Mac and select "Bluetooth", it should be listed whether Instant Hotspot is supposed by your hardare.