If a scalar field component has to be added to the Einstein field equations to solve dark matter/energy, then how would string theory need to be modified and do black holes still exist?

Refs:

*Dark Matter, Dark Energy, and the Fate of Einstein’s Theory of Gravity http://mathgradblog.williams.edu/dark-matter-dark-energy-fate-einsteins-theory-gravity

*UNIFIED THEORY OF DARK ENERGY AND DARK MATTER, TIAN MA, SHOUHONG WANG http://www.indiana.edu/~fluid/paper/report.pdf