I can take a stab and answering most of those questions.

What is so little info available? Because all three are made by companies that are notoriously tight-lipped.

Japanese missiles are never exported, so have seen no combat use.

In 1999, the Italian Air Force AMXs used Opher against Serbian targets.

There is not much information on the Type 99 Modified (AAM-4B). Japan’s Technical Research and Development Institute (TRDI) is understood to be developing a Ka-Band AESA seeker for this missile, which is expected to serve on the F-2 and F-15J. Work on the new missile probably started in FY2010, and a total of 56 F-2 are expected to be made compatible with it, a process said to involve a new datalink and an upgraded J/APG-2 fire control radar.

The goals of the Type 99 Modified programme are to extend the missile’s range and active-homing range; to improve its homing capability against manoeuvring targets and small targets such as cruise missile; and to increase resistance to countermeasures.

Development of the XASM-3 probably started in the early 2000s. It is intended to replace the Type 93 (ASM-2). It is powered by an integrated solid propellant ramjet and has a range of 200 km or more. Terminal guidance is reported to be via a dual-mode imaging IR and active radar terminal seeker. Measures such as shaping and the use of low-reflectivity composite materials have probably been used to minimise the radar cross-section.

The missile was first seen in 2006 when a Mitsubishi F-2 test aircraft of the Technical Research and Development Institute (TRDI) was seen carrying what were probably captive-test missiles. I have not seen any reports of powered and guided flight tests, but it seems reasonable to assume that these are under way, since the missile is expected to enter production in 2016.