If her "personal" emails have been recovered, then no one knows where the focus of the investigation lies. She took extreme steps to bury them, and her office tried to subtly get the company holding the backups to reduce the backup by narrowing the period they wanted saved down to 3 days. Outside of calling and saying, "Please wipe the server," this was the best approach if you wanted them gone. Presumably the space on the servers used to archive them would be released and written over. May even be the reason they chose a small private firm in stead of a giant firm with infinite drive capacity and forensics to recover data. A smal firm will have less recovery tools and will maintain less unused resources, meaning they aren't apt to hang onto something they aren't being paid to preserve. There are two problems however:
1. Internal emails at the private company reveal that staff were concerned that Hillary Co. was attempting to hide something based on the requests to narrow the backup window
2. The FBI has the will and sophisticated recovery tools
It's likely that the suspicious of the firm coupled with the FBI's sexism to devote resources to the investigation recovered all or part of what was wiped.
(Side note, an IT firm will generally have a redundancy scheme--whether saving parity bits to multiple drives attached to different arrays or to tape, to geo-redundant servers elsewhere or a combination of the above. Bet it makes everyone feel great that "above top secret data" was hanging out in these places.
Regardless, the fact the FBI shows no signs of rushing the investigation to accommodate the election cycle could be because the FBI (which took several months to go through the 50k "work" emails) could be going as patiently through the 31k "private" ones.)
The point is... All bets are off if the FBI has those emails, because they could be investigating Clinton Foundation business, things we don't know about -- or illegal Yoga routines.