Why not "their house is more lively than our house"?
Exactly, I had the same problem. "More lively"="livelier".
Wouldnt this be
There house is more crowded than our house
I think that's a valid translation. Ramai is sort of a weird word to translate, and there are several possible English words that work for it. Crowded, busy, noisy, lively... They all work, really.
Ramai has a positive feeling to it though, where crowded has a more negative feeling, I think.