SOLVED. Goosebumps-ish two-three book series about a boy and his family who move into a haunted house. [s]

[Samantha]

I read this series(can't remember if it was a trilogy or only two books) around 2002-2004. It was about an 11-12 year old boy who moves into this big old Victorian house with his parents and baby sister(maybe, brother, pretty sure sister). The house turns out to be haunted. I think only he experiences the hauntings at first and his parents don't believe him. I'm pretty sure they all get dragged into it a some point, though. The main thing that sticks in my memory from these books is that the main boy makes friends with the boy who lives next door and whenever they'd part ways, one of them would say, "see ya later, alligator," and the other would reply with, "in a while, crocodile."
They had a kind of Goosebumps-ish feel to them. Though I don't believe they were part of the Goosebumps series, they may have been by R.L. Stine.
I think one of the books had this big grand staircase on the cover with the baby sister(or brother) at the top.

[Tab]

Sounds like the "House on Cherry Street" Series.
https://www.goodreads.com/series/6427...

The first in the series is The Haunting

[Samantha]

That'd be the series! Thank you so much! I didn't think it would be that simple.