Naphtha is an aliphatic hydrocarbon solvent. n-Heptane is an aliphatic hydrocarbon solvent. Naphtha is a mixture of compounds. n-Heptane is a single, pure compound. Each of them will have their merits but the behaviour of n-Heptane will of course be more predictable.
The solubility in n-Heptane of any given extracted material will always be the same at a particular temperature. The boiling point of n-Heptane is always the same at a particular pressure. These factors could be considered advantages. The price and availability of n-Heptane relative to naphtha could be considered disadvantages.
Heptane could be used in exactly the same way as naphtha for pulls from an A/B extraction. It will freeze precipitate, as evidenced by the use of its temperature/solubility gradient when used for recrystallisations. It's entirely likely that the problem of fumaric acid precipitating, as when attempting a FASA method with naphtha, would also apply. Limited testing suggests that spiking the naphtha with a bit of acetone before adding the FASA helps to prevent this. Presumably this would also apply to n-Heptane, but I don't know as I've never tried it nor heard any reports of this. It seems very likely though.
If you do have a load of n-Heptane, it would be great if you could try this out. But, understandably, you might not want to if you can just freeze precipitate - although you might get a tiny bit more product out of the solvent with FASX.
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― Jacques Bergier, quoting Fulcanelli