So if someone used Edo tensei and then made the Edo use reaper death seal it wouldnt take the person in charge of the edos soul. Edos have souls and if they're made to perform the technique it will be their soul and the one being sealed whose soul will be taken. Therefore Edo tensei is the loop hole around reaper death seal drawback
There seem to be quite a few ways around Reaper Death Seal. There is the one you mentioned, but there are much easier ways too. A person could possess a body, like Orochimaru or someone in the Yamanaka clan, and have them cast the jutsu. Another possibility is to use genjutsu to make a person use Reaper Death Seal.