That would be getting into serious fraud, arguably criminal under CFAA. Normally Apple isn't interested in prosecuting these people as its just sideloading, which is some minor copyright violations and a security risk in their view, but if Facebook did it after having been banned themselves, having a written statement from Apple that these apps were violating, and then they go and pay a third party or deliberately make a shell company to defraud Apple? That could provoke a total business embargo between the companies which would suffocate FB.