Many Mythic Paths in Mythic Paths of the Lost Spheres support multiclass characters but as of yet there aren’t many multi-path mechanics out there despite the Dual-Path feat. But the possibilities are endless for path interaction and one such option exists for Worldsingers who are familiar with the aspects of the Will-of-All path:
For the Worldsinger AND Will-of-All mythic path from Mythic Paths of the Lost Spheres:
Song of Life Ever After (Mythic)
Your stories and song awaken the past heroic existences of fallen allies.
Prerequisites: Dual-Path feat, Hymn of Life and Awaken Past Life path abilities.
Benefit: When you activate your Hymn of Life you may spend a second use of mythic power while activating it, if you do the power of heroic rebirth sinks into the Hymn of Life. If an ally who is benefiting from the fast healing of Hymn of Life drop below 0 hit points, they are restored to a fully rested version of themselves that could have been accessed via the Awaken Past Life Will-of-All ability (see page 58 in Mythic Paths of the Lost Spheres for more information on past lives). Up to one ally can be restored in this manner per two tiers during any given activation of this ability.
You can get Mythic Paths of the Lost Spheres on: RPGNow or Paizo or d20.pfsrd.com!