After you made a map with visualmunge, is there any way to edit the title and description?

Yes, through the editlocalize.bat

[color=#FF8000][b]The FAQ / Everything You Need Thread Version 2.0[/b][/color] wrote:...
Localize
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• How to change mapname and/or 3 line world description

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Please take the time to look through the above thread next time. Thanks.

Would adding new modes be in that editor as well?

You can localize mode names that appear on the load screen with the localize tool, but that's it. To add in the actual, physical modes, it requires you to set up LUA's, REQ's, new ZE layers (if needed), etc. and edit the addme.lua.