I’d think that state legislatures in question could allot the electors according to congressional district. NE and ME already do this.
If that is done, don’t know if it helps Trump get to 270 or not.
I can’t imagine why legislatures would want to do that, or that they even can, if split electors is not in their current law. They will have to follow their existing constitutions and laws.
Most states are winner-take-all for electors. It gives the state maximum power in the selection of the President.
The only way California will ever go split, for instance, is if Pubbies get the majority.