Javascript Conflict?

SOLVED: scripts.pre.tpl in mychanges was where we added slim.min.js. Removed it and now the plugin works.

I installed a new module to display filters as dropdown select boxes. The issue is nothing happens when I select a filter option. Addon developer says there are other js errors causing this failure. I suspect there is some conflict in code that programmers have added over the years for certain functions. I'm lost when it comes to javascript. Need help if I have conflicting versions of javascript and where to correct it. Thanks

Three Console errors are:

Uncaught TypeError: Cannot read property 'step' of undefined
at String. (jquery-ui.min.js:6)
at each (jquery-3.3.1.slim.min.js:2)
at Function.l.hook (jquery-ui.min.js:6)
at jquery-ui.min.js:6
at jquery-ui.min.js:6
at jquery-ui.min.js:6
at jquery-ui.min.js:6
(anonymous) @ jquery-ui.min.js:6
each @ jquery-3.3.1.slim.min.js:2
l.hook @ jquery-ui.min.js:6
(anonymous) @ jquery-ui.min.js:6
(anonymous) @ jquery-ui.min.js:6
(anonymous) @ jquery-ui.min.js:6
(anonymous) @ jquery-ui.min.js:6

Uncaught TypeError: $(...).ajaxStop is not a function
at (index):2958
(anonymous) @ (index):2958

Uncaught TypeError: jQuery.ajaxPrefilter is not a function
at (index):2977


I've read where slim.min.js removes a bunch of functions so I think I need to comment it out.

Where would I look in code to comment it out?

FOR REFERENCE these are the lines in the page that call js scripts:

These two lines are from addons/mychanges/hooks/index/ that call: