Hello!
I don't have specific info on the families you mention, but I've been doing a bit of research in the same area - my Grandmother was from Creggan, just north of Ferbane (An F?ar B?n means "white grass.")
I'm just working into the generations beyond my great-grandparents so am just beginning to try and find info in the mid 1800s myself. I've been working with some cousins over there to try and fill out the tree. (I'm in NY.)
By the way, I did a quick search for "O'Neill" in the Griffith's valuation in Offaly and looks like your Hugh is listed there in Clonmacnoise - which fits the seven churches. If you look at the actual record at that link you can see he is one of a few dozen sub-lessors of land from Arthur McGuiness. (You can probably do the math on the amount of money Hugh's land holding cost him as a portion of the total and figure out about how many acres he had.)
Thought I'd throw a few useful links out there in case you hadn't seen these sites:
Offaly Historical & Archaeological Society has quite a lot of great resources.
Rootsireland has records for Kings/Offaly - although my results at finding records have been a bit spare there.
I haven't used them but Irish Midlands Ancestry can do research for a fee:
There are some very good books about the area - might be a bit tough to find, but in addition to be available at the Historical Society, they pop up on eBay and online shops once in awhile:
A Land by the River of God - A History of Ferbane Parish , Brendan Ryan
Falling into wretchedness: Ferbane in the late 1830's
The diary of an Offaly schoolboy 1858-59
If I can help with anything, let me know! I can be reached via my site at:
http://currach.johnjtierney.com/contact/
Best of luck!
John Tierney