Regarding bonds with the company, as far as I'm aware, as an FO, if you meet their stated requirements (1000 hours / inc 500 multi eng), you are bonded. If you are offered a post with hours less than this requirement, you are expected to pay for your rating.
I would say slim chances for a NWI base as a newbie. As people may move on, I would think its likely there are crew up in ABZ or other bases looking for a southerly move already on the base transfer list.
As a new FO joining, I would set your sights on Wick or ABZ as an initial base. Hasn't always been the case, but at least you won't be disappointed if another base is offered!
On the whole though, in my opinion, whilst Eastern may lack in some areas, they do make up for with a great bunch of crew. Good luck to those applying.