1. Piggy-Bac transposon system is a system which has been developed to 'carry' and integrate your gene-of-interest into a target genome. Please see the link below for brief description of this system. Also, see the attached article.

https://www.systembio.com/piggybac

2. Significance: the transposons integrated in the genome can be re-excised/removed, footprint-free.

3. From provided info, except the plasmid carried your gene-of-interest, you need another gene to express transpotase

4. You can search for related published papers and find out the details

As I understand your question, you want to reverse the mutation caused by a transposon. If you want to do this in vitro, the simplest way is to just cut out the transposon using appropriate restriction enzyme(s) and then religate. If you want to do it in vivo or in the intact organism, use the CRISPR method