Hash mismatch is usually a bad download, or sometimes less frequently, a result from Filtering or SSL Inspection that's making files 'safe' but in turn changing the hash and triggering our protection from man-in-the-middle attacks. If that deployment started, as in it passed the disk clean portion, you'll have to restart the deployment with USB media.
Other devices that are remaining in pending; the client is not processing new messages from the console. Make sure there isn't anything stuck from the any previous deployments (Like C:\WIndows\Temp\SD or C:\Windows\Temp\!sdspk existing) - If so, look in them to see which package was last deployed, kill the task in task manager, and then remove those directories and restart the SD Client service.
If it persists, email support so we can collect log files and investigate further.