U.S. suggestions of what jet fighter aircraft Japan needs are hard to take seriously. Consider the link to the Reuters story below.
The Super-Hornet is a strike aircraft that happens to have some air-to-air ability. It is the slowest aircraft of its kind. From brake-release to intercept, it is the slowest jet you can try and fit into this competition.
The F-35 was never intended to be a prime home defense interceptor. Like the Super Hornet, it will not be able to stand up against emerging threats in the Pacific Rim.
The Eurofighter Typhoon is the least-worst option for Japan.
The best option? That would be the F-22.
The U.S. has let its allies down by allowing its leadership and common sense in the military aerospace industry wither and then die. If the F-22 is not an option, the U.S. is unable to provide any credible solutions for air supremecy problems.
The hard truth is this; if your fighter aircraft has little chance at beating the F-22, it also has little chance of beating the PAK/FA.
U.S. allies will have to look elsewhere for air power solutions. Korea is.