Niki .. you used the 'R' correctly in 18, so no go for 19 .. Gail got it
Gail .. peek is only 4 letters and I'm looking for 5 or more .. and then I discovered the mice were out and about again and I missed an 'O' on the top line making the solution peekaboo .. so I'll give you "peek" and add 'a boo' to boot.
All other solutions are correct