Firebases ship mod is 100% compatible, although it will say its not. I assume that cause it changes some backgrounds only, that Realspace lite is (haven't checked it out), and ships that are in scripting might be. Note the might, cause the starviper and other ships have the same nickname in my mod as in the aps shippack.
Other large mods will definately NOT be compatible - at all.
Ships should be okay, but a general rule of thumb - if the ship is in their already, then its not compatible. Firebase has some ships in their, but in his LATEST edition of the mods, he has renamed them in the shiparch.ini file - which means that they WON'T be incompatible at all - they will work 100%
Apart from that - openSP will work, and maybe a few others, but i raelly doubt it. Nearly all files i have edited have changed values, therefore, when you have some mods that change speed for example, activating them - they won't find the correct place cause i changed it etc. This will happen for lots of ship mods too - as they will search for ship selling points, but they are just not there, as my market_ships.ini is edited down to make it easy
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So, i only know two that are, OpenSP and Firebases stuff. Even MY openSP mods aren't compatible!