Sharepoint Custom list issues after migrating 2010 to 2016

We had a migration on our sharepoint farm from SP2010 to SP2016 and several things in our custom list forms really appear off and was looking to see if someone else had experienced this and might have a solution for correction. We do have the opportunity to re-migrate so we can make changes on the SP2010 side to prepare for final migration which will happen at the end of next week.

Issue 1 any person or group field on our new or edit forms show up weird, the two icons for check names and browse people directors are now outlines in obnoxious blue lines

Issue 2 the check names function appears to work but the browse triggers an error to the screen JSON is unidentified and rather than getting the old pop-up window it builds an addition to the bottom of the screen for a people selection which is very ugly. And it does not appear that new addition to the bottom of the screen works it just spins.

Issue 3 One of our very standard forms shows up as completely unusable screen shot attached enter image description here

Issue 4 When we include a people or group field on a display form we get a weird icon in front of the actual value see attached enter image description here

Issue 5 We also get a lot of these very strange pics pop up wherever we try to put the textname of a user or group on a page see attached enter image description here

THese are all show stoppers for us to migrate so we are scrambling to try and find answers to fix on the receiving end or on the front end before we migrate again.

Thanks for any help provided