Currently, elementary OS Loki is running Ubuntu 16.04 (or .10, amirite?) under the hood. My question is: will the guys working on elementary OS update from the former version to 17.04?
No. This is because Ubuntu based distros that are not official spins like Linux Mint and elementary OS are based on the latest LTS versions. This is done because LTS releases are more throughly tested and are proved to be very stable. So the next elementaryOS version bump will occur when 18.04 LTS will be released.