Is it common to be given 6 months for a minor revision outcome? I received a paper back with a verdict of minor revisions on August 30th. Both the letter from the editor and the scholarone submission system states 'minor-revision.' 

I've read the reviewers' comments very carefully, and everything is, as the editor states, a minor revision. Nothing requires me to re-analyse the data, or engage with new work. Rather, most revisions are of a small nature, such as fixing up some grammar and clarity errors, ensuring consistency with terminology, and further developing a couple of sections (drawing out the analysis a bit more, being more specific about methodology). This would at most, take a week or two, and then an additional few weeks to get a peer to proofread for me one more time before submission. 

However, I've been given until February, 2016 to complete them! For a minor revision that seems like a lengthy amount of time. So now, I'm unsure as to whether they've just given me a lengthy timeline because the journal itself articulates a 6 month turnaround time for peer-review (it took about 5 for this article), or if the revisions are meant to be more substantial. 

I read this What is a reasonable time to resubmit revised papers after they have been peer reviewed? but didn't find it helpful. 

Is it common in some fields to be given 6 months for a minor revision outcome that will only take a few weeks? I'm concerned that I should be making substantial revisions despite the letters indicating otherwise due to the time-frame provided. 

My field: Social science
I suspect that what happened is that the editor used a web form to notify you of his/her decision, and to send the referee reports. 6 months is probably a default in the software which the editor did not bother to change. The only thing it is likely to indicate is that the editor sees no need to rush you, and is happy to receive your paper when you're ready.

It's certainly a good idea to finish your revisions much more promptly, and it will likely result in your paper being accepted sooner.