For reasons that escape comprehension, neither Blackrock (v0.6.5) nor Citadel (v0.6.3) spawned fleets are showing as leveled (bug? visual gaffe?) when loaded alongside v1.3 of Starsector+; this issue does not extend to the v1.0 release of Interstellar Imperium, nor the v0.59b release of Exigency Incorporated.
I was able to get around this issue via a rather messy method; I opened up Blackrock's and Citadel's respective .jar(s) with WinRAR and deleted any .class files (in 'data\scripts\world' and associated sub-folders) with *Spawn* in their names, which allowed the *Spawn*.class files in SSP.jar to load instead, without opposition.
Which shouldn't even be an issue normally, as SS+'s mod_info.json has a 'name' field (using a '$' instead of 'S') that should allow it to take top priority over all subsequently-loaded mods, but for some reason(s), that wasn't happening with the *Spawn* files for the Blackrock and Citadel mods. Or else those mods were coded differently, or something.
*shrugs helplessly*