Did you see the mod Biter Hates Concrete and came up with this idea?
Or is it a supposed to be a variation of the Seablock mod maybe?

I have not seen the Biter Hates Concrete mod. I came up with the idea just as a simple first mod to get me started. I like the expansion sort of gameplay from minecraft skyblock mods so I guess it was sort of inspired by that

Ok.
I really like the idea of cramped space mods and have tried several of them. But I never get very far because I can't think if I don't have vast open space, undisturbed time and limitless resources. I just lose focus and energy :/
I'm too used to building in my megabase or in creative mod. But I'm making some blueprints there now for early to late game. I might make some smaller ones that I can use for mods like yours to allow me to get past green science.

I've tried NESTT (way more cramped than any ribbon world), Factorissimo (before the release of bigger buildings and entire base (except power and smelting and mining, but all was the goal) inside a single building on nauvis!), some underground digging mod and deathworlds where the space is really limited by the natives.

Are you playing The Floor Is Lava with "Alien Biomes" lava biomes?

I don't play any kind of lava biome. The name "The Floor Is Lava" comes from a children's game where you travel across the room using couches and pillows, never touching the floor. Come to think of it, I suppose that's what the inspiration for the mod is

I know of the game. Im just saying that the lava biome (since all biomes do) would actually kill you with this mod it seems like a good thematic fit.

But it does answer the question :)
I assumed you came up with the mod from other inspiration sources and then named it after the game.