Overhauling practice/teaching space

[Octavian]

I'm in spring cleaning mode and am trying to get better use of my equipment and do it in minimal space. Here's what I have:

Markbass LM II (for gigs)
Epifani PS-112 (for gigs)

Acoustic B10 w/ aux in(for teaching)
Squier ?? (for teaching)

TEACHING & PRACTICE
For space reasons, I'd like to sell the Acoustic & Squier and just use the Markbass and PS-112. Should I get a mixer or ??? to run two basses into the MB? I'd also like to be able to plug in an MP3 player to work with songs and backing tracks.

QUIET PRACTICE
Since my music area is in the living room I sometimes have to grab my gear and head off to the bedroom to practice. I'm thinking of getting a headphone amp for this, such as the Cafe Walter...which seems to be highly recommended. I can run the headphones and my iPhone to it and be good to go.

LIVE
I don't gig much these days but do have a show this summer where I'll be playing a bunch of 70s-90s covers. I'll be going direct so no worries about an amp or cab. I would like to use some effects for a few of the songs (distortion and chorus), but sold all of my pedals a few months back. I had plans on getting a Boss GT10B and using that for any effects I needed. I see that I can also use headphones on this and it could be used as a big headphone amp, but I'm not seeing where I could plug an MP3 player to it to practice tunes or play against backing tracks.

Any suggestions on how I can streamline everything as much as possible to get a rig for teaching/practicing; live FX; and portable headphone amp that I could take from room to room.

[Octavian]

I forgot to mention it might be handy to be able to pull two sets of headphones from the rig so I can have one and my student the other...sometimes it would be nice to crank up the volume without vibrating the rest of the house!