Humphrey used to steal my plant pots and also the little plastic labels I put in with my seedlings! My garden was full of surprises for the first two years!!
As for sitting in the garden howling - he‘s only ever done than twice, the first time my sons were dog sitting because we‘d gone away for the evening (first time we‘d left him) we have noticed that occasionally he‘ll ask to go out in the evening and then he‘ll just sit on the lawn staring into space, he did it yesterday actually, and we have a full moon at the moment.
They do say that wolves howl at the moon, no idea if that‘s true or whether they‘re putting out a call.
.I suppose its possible that if Maisie has been in a kennel with other dogs, she might be trying to connect to them, as Humphrey did when we weren‘t there, but then I‘d imagine once she‘s settled down with you, that will soon stop. Interesting