"Was JL-2 a failure?"
It's likely that the JL-3 comment was made in error - what they're calling "JL-3" might be what we call JL-2A. It's ultimately a matter of missile dimensions; just from eyeballing the JL-2 during the 2019 parade, it's a small missile that matches the DF-31 dimensionally. It's highly unlikely that an SLBM derived from the DF-41 would be that small. Unless the 09-IV has launch tubes that can accommodate a much larger missile than the JL-2 (in which case, why waste the space by loading a small missile to begin with?), or at least newer submarines do, this just doesn't pass the smell test.More important take from that is, providing the jl3 comment wasn't made in error, is that jl2 and jl3 are compatible enough to be used on older submarines. Something like trident c4 being compatible with subs that carried earlier Poseidon c3 missiles.
What source say JL-3 derived from DF-41? and what is JL-2A?It's likely that the JL-3 comment was made in error - what they're calling "JL-3" might be what we call JL-2A. It's ultimately a matter of missile dimensions; just from eyeballing the JL-2 during the 2019 parade, it's a small missile that matches the DF-31 dimensionally. It's highly unlikely that an SLBM derived from the DF-41 would be that small. Unless the 09-IV has launch tubes that can accommodate a much larger missile than the JL-2 (in which case, why waste the space by loading a small missile to begin with?), or at least newer submarines do, this just doesn't pass the smell test.