Migrate WP site from webhosting to localhost

I need an expert in WP installations and migrations who will migrate WP site that is not being used to localhost. The goal is to save site to laptop and if possible make it available online only part time using Dynamic DNS. I already copied site files over FTP, mySQL database, installed XAMPP, restored DB and copy the files. Had a lot of error that I tried to fix in PHP files but in the end I didn't manage to get it working. WP site is older so I guess it used an older PHP version and that's why there are errors. So basically there shouldn't be too much work I think. I also tried going the way to only copy the content of her site and leave the core PHP files from the new version. It gave me some errors so I didn't follow that way to the end because the plugins was giving some errors. This is done for my friend so the work will be done over TeamViewer and you can also expect my support and cooperation.