Split receptacles are not available as GFCI type.

Can 2 GFCI outlets share a neutral?

"The only way to use two GFCI receptacles to provide GFCI protection to more than two total receptacles on a shared-neutral circuit is to stop sharing the neutral after the GFCIs - by using two seperate 12/2's, or 12/2/2.

How many outlets can you run off a GFCI outlet?

There's no limit. A standard GFCI will protect up to 20 amps, drawn from any combination of receptacles, either the built-in one or any number of additional ones connected to its load terminals.