When somebody is the best friends with somebody on Snapchat, does that mean that he/she also sends snaps to this person recently? Or just in general? Even if he/she hasn't Snapchat him/her back?
Yes, when you see a username in the list called Best Friends, it means that the user talks with him/her on a regular basis. If they send snaps only at certain times then it means they chat periodically.
The Snapchat developers also created a page where you can see everything related to Best Friends. Access the following link to reach the desired page: https://support.snapchat.com/en-US/a/bestfriends