The iPhone backups are located in:
/Users/MYUSER/Library/Application Support/MobileSync/Backup/IDENTIFIER
Where USER = your username and IDENTIFIER is the iDevice you wish to recover from.
The hashed filenames you need are:
1b6b187a1b60b9ae8b720c79e2c67f472bab09c0 WhatsApp
3d0d7e5fb2ce288813306e4d4636395e047a3d28 SMS and iMessage
2b2b0084a1bc3a5ac8c27afdf14afb42c61a19ca Call History
31bb7ba8914766d4ba40d6dfb6113c8b614be442 Contacts / Address Book
2041457d5fe04d39d0ab481178355df6781e6858 Calendar
ca3bc056d4da0bbf88b5fb3be254f3b7147e639c Notes
4096c9ec676f2847dc283405900e284a7c815836 Locations
These files are sqlite3 database files so if the data is intact then you can load them into sqlite3 and query them but if you wish to recover messages that were deleted on the phone then you are relying on the fact that the database does a lazy delete and doesn't scrub the data but marks it as available for overwriting.
This means that the sooner you try to recover, the more likely it is to be uncorrupted by overwriting.

Extracting UNDELETED data by sqlite3 query

Call History

sqlite3 PATH_TO_BACKUPS/2b2b0084a1bc3a5ac8c27afdf14afb42c61a19ca
SELECT address,datetime(date, 'unixepoch'),duration FROM call ORDER BY 2;

WhatsApp History

sqlite3 PATH_TO_BACKUPS/1b6b187a1b60b9ae8b720c79e2c67f472bab09c0

SMS and iMessage

sqlite3 PATH_TO_BACKUPS/3d0d7e5fb2ce288813306e4d4636395e047a3d28
SELECT datetime(date + 978307200, 'unixepoch'),, is_from_me, text FROM message JOIN handle ON message.handle_id=handle.ROWID ORDER BY 1;

Contacts / Address Book

sqlite3 PATH_TO_BACKUPS/31bb7ba8914766d4ba40d6dfb6113c8b614be442
SELECT ROWID, first,last,value FROM ABPerson p JOIN ABMultiValue v ON p.ROWID=v.record_id;

Extracting DELETED data using forensic methods

Coming soon. I have written tools which scan the files byte by byte looking for known tokens and extracting as much data as possible.