I could be wrong, but it seems likely that +Vigano recommended Taylor Marshall to Trump, to be on Trump's advisory board.
Marshall said recently in one of his videos that +Vigano directly sent him a communication, which means, I assume, that Vigano is in contact with Marshall. It seems that +Vigano mainly works with Opus Dei affiliates. I hope that Trump does not become sympathetic to Opus Dei as a result.