I doubt very much there are any themes from Elgg 3 available yet.

Have a look at http://learn.elgg.org/en/stable/appendix/faqs.html?highlight=disable#white-page-wsod

I haven't tested if this still works in Elgg 3

Or you can use the commandline to disable plugins

http://learn.elgg.org/en/3.0/intro/elgg-cli.html#available-commands

Well thanks for the link, i was able to isolate it to Elggbook_pro.

the CLI is amazing..

It looks like the method with creating the file mod/disabled still works on Elgg 3 to prevent the plugins from getting loaded. Though it looks like some cached views (like custom_index index page) still get served as long as the cache isn't flushed.

You have answered your own question. Where is the .live coming from?

Refer to the source code that you have shared:

$("span.custom_fields_more_info").live('mouseover', function(e) {

You are using an outdated version of the Profile Manager plugin. The jquery "live" function is no longer working with the jquery version that comes with Elgg 2.x. The jquery "on" function has replaced it. In the recent versions of the Profile Manager plugin the deprecated usage of the live functions should be fixed for quite some time already. So, try the latest version of Profile Manager from https://elgg.org/plugins/385114 for Elgg 2.3 or maybe even better use the latest version from https://github.com/ColdTrick/profile_manager/releases (sadly not released here on the community site).