It won't be an issue in the sense of the Story anyway. In terms of Molly's actual lifespan, 10-20 years (About what Bob gave Lily) isn't that 'long term' really.
Already we've seen her struggling with the Mantle literally body-jacking her to force her to fulfill her role as a good little robot, to the point where she can't even speak as she chooses.
But she 'chose' to be in the general vicinity of a faerie queen when they died, so it's not a breach of free will to be literally enslaved and have your body puppeted like a marionette! (Seriously, between that lame-ass excuse and Michael's House having holes in it's defences you could drive a Panzer Division through, Heaven needs to step up it's game).