It would be worth trying. It could work. I am not one of those that says a "plan will work". I believe we need to actually try things and be willing to adapt and say "that works", or "that doesn't". It likely would produce a combination of things that work, and do not work.
My only real thoughts are on the securing the border part. If there are sensors will they be easy to trip so cameras are constantly firing off. People may stop paying attention unless as you indicate those that are doing this by crowd sourcing are compensated in some way. As far as wild life moving back and forth, I personally do not know how necessary that is or is not the the ecology of the area. I do know that a physical wall of sufficient design would be likely to be more of a deterant that sensors, but it would still need to be monitored with sensors as well. Sensors can often be defeated and they can be overly sensitive each which present their own set of problems.
Also, currently we have a lot of people NOT enforcing laws. That is a problem. If we do as you indicate that would likely still be a problem. This is true of many "laws" beyond simply immigration though.
Wildlife migration is a huge issue along the border, and is one of the reasons the border security projects become stalled. It is completely unrealistic to build a high physical wall along the thousands of miles of relative wilderness that divides the USA and Mexico and the USA and Canada. Also, it is easy to build a tunnel under a wall. With hidden sensors and cameras, it is possible to include a large area without hindering wildlife in any way.
It is very easy to tune sensors so that they recognize a heat signature that is of the size of a small human, so that only larger animals and people will set them off, and the sensors cannot be spoofed by simply moving slowly through the target area. They can also be well concealed, and redundancy is a huge factor.
Volunteers really do not need to be paid - millions of Americans donate their time to such causes all the time, and these days there are lots of people who spend all day looking at their screens anyway. It will be entertaining to look at the feed, because usually the livestream will include a large mammal such as a deer and the volunteer will be looking for a human hidden amongst the animals. Deer will behave differently if humans are near. Those who fail to click on the camera feed when they are signaled about a potential incursion can easily be removed from the roster.
This plan is designed to address the issue that law enforcement officers are hesitant to enforce laws that they perceive as being unfair. By implementing a fair system for everyone to become legal, this incentive to enforce the law unequally will disappear.