Employment Lawyers Can Answer Your Employment Law Questions
That would appear to be unreasonable and unenforceable. 5 years and any surveying company anywhere? The courts wouldn't allow that. It's unenforceable as it's unreasonable.
That appears to relate to clients of your employer and would be permissible. That is not a blanket ban. It is to protect the company's existing business.
Yes you can, as long as you don't breach the terms of your agreement with your existing company.