1. To what degree do miners collaborate with each other (for example: purchasing miners in bulk, purchasing datacenter services , electricity etc) ?

I'd say it depends on from where you are getting your hardware and/or services.  For example, unless you're purchasing a large quantity of hardware from Bitmain, chances are you're just going to hit their website and place your order.  On the other hand, when Spondoolies started selling their SP10 last year, I spoke with Guy (the CEO) via email a number of times, and worked with Zvi (their lead engineer) with some firmware problems that led to the gear not working on p2pool.  He addressed the issue and provided me with a fix within 24 hours.

If you're purchasing gear used, then there's typically quite a bit of interaction and collaboration.  I'll continue using the SP10 as an example here.  When I sold it, I communicated quite a bit with the buyer, and reconfigured the miner to point to his pools prior to shipping it to him.  Also, escrow services provided by a number of the trusted users here on the forums lead to greater collaboration between folks.  There are also users here who sell services (like providing hosting, power supplies, etc) and run their own hardware projects (GekkoScience is one I can think of off the top of my head).

2. other than Bitcointalk, and reddit forums,  are there additional "spaces"/forums/groups/other that miners use to catchup on things and/or use for discussions  ?

There are a number of sites out there dedicated to crypto in one fashion or another.  Most coins have their own boards and websites.  There are dedicated news sites.  Twitter is another large forum for spreading information.