Reina, 30, is expected to join the Serie A club on a season-long loan after Reds manager Brendan Rodgers admitted the Spain international's wage bill was prohibitive following the arrival of Simon Mignolet from Sunderland for £9million.
The move would see Reina link up with former Anfield boss Rafael Benitez and goalkeeper coach Xavi Valero.
Argentina forward Higuain was a reported initial transfer target for Arsenal before the player revealed Jose Mourinho was keen to bring him to Chelsea after their time together in the Spanish capital.
Benitez is in the market for a goalscorer after Edison Cavani's move to Paris Saint-Germain for 64.5m euros (£56m) earlier this month.
Napoli will have to pay in excess of £30m to sign Higuain on a permanent deal.