My Haunted House (Araminta Spookie, Book 1) by Jimmy Pickering

This house is not for sale
Araminta Spookie lives in a wonderful old haunted house, but her crabby aunt Tabby wants to move. Aunt Tabby is determined to sell their house—Araminta has to stop her!
With the help of a haunted suit of armor named Sir Horace, a ghost named Edmund, and a lot of imagination, Araminta hatches a plot for an Awful Ambush that is so ghoulish, it just might work!