[jakebasile]

The best solution for the name collision problem that I've seen so far is used by Discord and Battle.net, both in the gaming space where username is often much more prominent than the real name.

You can set your username to whatever you want (e.g. "jakebasile"). You then get a randomly assigned four digit number appended to the end (e.g. #5024). To add someone as a friend, you need the full username#0000, but thereafter it is not needed. To mention someone in a chat (in Discord) you type @ and then start typing - it will match on either the user name or display name, but only complete the user name. The key is that when you actually send the message it will show that user's display name in chat and notify them as you'd expect. Display names in discord can be overridden at the server level and in Battle.net games there is the concept of Real ID instead which you can choose to share your real name on a per person basis.

In both of these situations you are only using one account and one username across either multiple games or multiple servers. This avoids having to use many different accounts within the same application which is one of my primary gripes with Slack.