Update from Snow Leopard before migrating to new Macbook Pro?

With apologies for being so confused... I have an older 15" Macbook Pro running Snow Leopard (10.6.8) and just bought a new 15" Macbook Pro with Retina Display running Yosemite (10.10.4). I know I'll have to update or completely replace some older apps, but -- do I need to update the Snow Leopard MBP to Yosemite before using Migration Assistant to transfer all my files & apps to the new MBP?

I've established that Migration Assistant will not overwrite newer versions of bundled apps with older versions and/or won't even transfer over the bundled apps from Snow Leopard (please tell me I'm right, please oh please), but the wording in several articles I've read has my over-active imagination wondering if I have to update the older MBP to Yosemite before using Migration Assistant. Years ago I used Migration Assistant to move everything from an even older MBP running MacOS 9.1 to the Snow Leopard MBP with minimal complications, and am wondering if I can repeat the "jump" without an upgrade from the now-creaky Snow Leopard MBP. (For the record, having to update the old MBP first would be A Bad Idea right now.)