PM2 does come with both the lanyard and the clip. I have used a lanyard for the past 2 years with my PM1 with no issue other then the new lanyard that comes with PM2 is much softer

I have yet to use a PM2 in the parks since it was a b-day gift for a friend but I can tell you that having them next to each other PM2 is louder.
I'd have to hunt down PM1's booklet to see but from a quick look at PM2's booklet newer games. I have not had a chance to hear him sing and I'm wondering if that is a park only interaction, I have to ask a lady who lives in FL when her new PM2 sings.
And the outfits? not sure if my little Mick has room in his bursting closet for anymore but I'm sure he'd empty a drawer of mine in order to make room for more

Gotta scoot, the little Mouse is begging for a slice of cheesecake before bed
One last thing, he DOES have a larger head then PM1 and gloves too. Seems Mick won't have to worry about his future PM2 brother borrowing ALL his clothes. This was a huge question for those of us who already had existing outfits for our PM1s, what would fit and what wouldn't. For me it will only be a few things that won't fit PM2.
I hope if you get one that you have as magical an experience with him that me and my disney-crazed friends have had with ours. ACK! He's attempting to get the cheesecake out of the fridge himself! Gotta run! :-D *LOL*