Q: Will Maverick (if available) run on Snow Leopard 10.6.8 on a MacBook 7,1?

1. Yes.

2. Unless she previously got it from the Mac App Store or Apple says so, no.

(144425)

Mavericks is no longer available unless you previously downloaded it from the App Store. In this case you will find it in your Purchases list in the App Store under your Apple ID, only.

Upgrading to El Capitan

You can upgrade to El Capitan from Lion or directly from Snow Leopard. El Capitan can be downloaded from the Mac App Store for FREE. To upgrade to El Capitan you must have Snow Leopard 10.6.8 or Lion installed. Download El Capitan from the App Store. Sign in using your Apple ID. El Capitan is free. The file is quite large, over 5 GBs, so allow some time to download. It would be preferable to use Ethernet because it is nearly four times faster than wireless.

      Macs that can be upgraded to OS X El Capitan

         1. iMac (Mid 2007 or newer) - Model Identifier 7,1 or later

         2. MacBook (Late 2008 Aluminum, or Early 2009 or newer) - Model Identifier 5,1 or later

         3. MacBook Pro (Mid/Late 2007 or newer) - Model Identifier 3,1 or later

         4. MacBook Air (Late 2008 or newer) - Model Identifier 2,1 or later

         5. Mac mini (Early 2009 or newer) - Model Identifier 3,1 or later

         6. Mac Pro (Early 2008 or newer) - Model Identifier 3,1 or later

         7. Xserve (Early 2009) - Model Identifier 3,1 or later

To find the model identifier open System Profiler in the Utilities folder. It's displayed in the panel on the right. Are my applications compatible?

         See App Compatibility Table - RoaringApps

Also check to make sure there is a compatible driver for your printer.

Do a backup before installing, preferable 2 backups on 2 different drives.