I am considering to use a service such as Songtrader or Artist.io for promoting my song. Plus, for making money. Already registered to DistroKid, so I am wondering if I can do it even though I am a member of the other publishers.

In addition, I am also wondering if I can use both of Songtrader and Artist.io. Or should I use only one?
Last question is that whether there are more service besides Songtrader or Aritst.io.

 

You can publish your songs by distrokid and songtradr at the same time. You can see the option at the last page of distribution. I don't know about artlist, try to ask them directly.