Are you testing rj45 plug or keystone jack

What tester are you using? Do you have a multimeter or an ohm meter available

Rj45 crimper should be good for cat5 & 6. I personally try to avoid crimping rj45’s and use a keystone jack and patch cord whenever possible

I would say connect the camera and see what ya have before rerunning the cable. I would say try reterminate both ends but if you don’t have the DTX to retest it don’t matter. the DTX will show you what pair is giving you problems.

That is a telecommunications artifact. You should put a picture frame around it .

If you do not have a land line phone or a security system you can get rid of it . Just tie a pull string on it when doing the demo work