No, it’s not possible… Well, for lights it’s definitely not. BSP does not save all information that MAP format does.
Explanation: After you compile the map and load up BSP in the game, you can notice that it does not have lights/shadows at all. That’s because you have to “bake lights” in another compile process, which creates external static lightmaps in your maps/mapname/ folder. These image files are source of lighting in-game…
So to sum it up, BSP file doesn’t include most of lights / light entities, meaning that you won’t get them in the decompilation.
Additional info: It is possible to keep light entities in BSP with -keeplights or something like that… But noone uses it, since it’s useless and adds on file size. It’s also possible to keep lightmap info inside BSP, quite ancient way to compile lighting. But I don’t think it helps to decompile light entities, which are still not present in BSP file.
Textures alignment… I don’t know much about this process. However, converting BSPs to OBJ format used to keep right texture coordinates… Don’t know why decompiling doesn’t do that.