merging stereo with ht, can anyone please help?

Up until now, my audio life has been easy. In my den, a HT system utilizing Sherwood Newcastle 1m-9080 5-channel power amp and AVP-9080R preamp. In my great room, a dedicated stereo utilizing a Grant (English brand) tube preamp, Acurus stereo amp and Dunlavy II speakers. Now, baby is on the way, den is mutating into nursery, and I am trying to blend HT and stereo, with decidedly mixed results. Here's the main issues:

What I'm planning on doing is utilizing the Newcastle amp for center, rear, and subwoofer channels, and my Acurus amp for the Dunlavy fronts.

1. I want to use the Sherwood Newcastle preamp for DVD source and my Grant preamp for CDs. Can I run cables from both preamps to the Acurus amp, and connect with a Y cable into the stereo inputs? If so, will any damage ensue to any components? What happens if I mistakenly play a DVD and a CD at the same time?

2. Can I run a subwoofer cable from both preamps to the subwoofer (M&K), and use a Y connector to input to the sub? If so, will any damage ensue to any components? What happens if I mistakenly play a DVD and a CD at the same time?

Any further thoughts/ constructive criticism welcome! Thanks for your help, oh great Goners.

Regards, Ben