A Few Questions About the System Editor

Hi everyone, i just wanna know - as a no english player - what, does the options when you place a structure on planet do , like :
No features / Mergeable / Flooded ( on moutains for exemple )

And also, i've played the galactic war and i saw 3 metal planets,
First one was fully operational , the second one was half build/finished like the death star in the first trilogy, and the third one has no catalyst/whole on it

I've found nowhere in the system editor option to play with the unfinished metal planet or a way to desactivate catalyst, and i wonder where i can find there if they're not available in the Editor, i'm pretty sur the game have them inside it's files , and no mods seems to let us play with these specials metal planets

Thanks for reading and sorry if i've made any english mistake

I haven't found a way to place a half-finished metal planet, but you can remove the catalyst points using advanced edit mode, then selecting and deleting the catalyst node circle thing.

Thanks for that, because catalyst are overwpowered sometimes ^^