I use apricot brandy or Grande Mariner all the time and have on rare occasions used peach shnapps both as an inject or in a mop. I love it. I prefer it as a glaze better than when its enjected because I feel that with it on the outside you initially get a hint of the apricot or peach flavour and then you get the taste of the beef flavour rather than an overall fruity meat flavour. Hard to explain.
The only time I smoked squash I burnt the hell out of it. Zzzzzzzzzzzzzz!!!! so no help to you there.
If I were to do squash again I'd make it into a thick soup and then smoke it for a couple of hours at 210f adding a bit of heavy cream when it was done. I'd stir it every 1/2 hour or so. I have done tomato soup like that in mesquite smoke and really liked it.