by my experience is not a good idea. Google is now looking if topics of the redirects are the same of the destination.. and it's proven that G do not like many redirects a part if you move your site to a new domain .. what should be better is to create contents within these sites, host them (on different hosts) and then link naturally to your site (without footprints) .. a sort of private pbn works well if done properly.
Well buying any links from a different industry to get link juices and trick search engines are considered
back hat.