Tier 4 - dependant

[Renni_Aman]

Hello All,
I desperately need some advice (solicitors all have different views...each visit costing my wallet to decrease significantly).

I am in the UK (legally, under a combination of student, student visitor and PSW visas) for 9 years and 4 months.
My boyfriend is in the UK for 11 years (2 of which is legal stay and the rest battling cases of failed asylum, legacy and FLR(O)).
We have been together for 8 years and 9 months (to date).
Last year April he applied for FLR(O) and got a refusal letter in August 2013. He contacted his solicitor and they did another investigation into the case and was granted a 6 months DLR 07 April, 2014 (until 07 October 2014).
My current PSW visa will expire in August 2014, which I intend to move into a Tier 4 student visa (Doctorate course for 3 years).
I am due to apply for 10 years ILR in December 2014.

My Questions:
1. Given the short period of time my boyfriend was granted, I was wondering whether I can add him as a dependent on both my student and ILR visas applications?
2. Would this have any effect on decisions on my case?
3. Is there any chance of just one getting through and other fail / or if one fail, then it would lead to both of us being refused?

Thank you for your response.