Is this safe?

What do you think about this connection methods?
1. My preamp has one set of balanced input only. Can I use Y- splitter to connect phono stage as well as CD Player ENSURING that at any time I have ONE front end on?
2. I input my phono stage out put in straight to spare amp I have. From that amp I would another set of speaker wires. One set is from my preamp for my CD source. Once again I would have to make sure ONLY one amp is on at any time.

You can only safely split outputs not inputs. You should get an outboard switcher.
Don't do either thing you're talking about, both bad ideas. Just manually swap the wires at your preamp's XLR input when you want to change to the other source (with the volume off of course) -- probably what you've been doing. A little inconvenient, but works with no technical problems or sonic degradation.
Option 1) You won't hurt anything but each source will see as its load the output impedance of the of the other source in parallel with the input impedance of the preamp. Since the sources will generally have a low output impedance this usually results in low volume. In addition nonlinearities in the powered off source may introduce additional distortion. Not recommended.

Option 2) Once again, each amp sees the speaker impedance paralled with the output stage of the powered off amp. Typically this is a very low impedance. This could result in damage to either or both amps. Don't try it.
Thanks guys. My dealer said the same thing but just wanted to verify, before I do anything drastic.
Why not just get some good RCA/XLR adapters from Ayre or BAT and try it out. If the sound isn't good enough just sell them.