Yet another low gpa question and other issues

[modricplayer]

Hello all,

I will try to be concise about my (unusual I guess) journey. I'm currently on leave (authorized) from my Ph.D. in Computer Science (I barely started my second year) in a highly ranked university in Asia. During the last year, I had a two-body problem. My significant other could not follow me due to visa issues (not able to work in the country where I was doing my Ph.D.). While I was back to my home country to solve some issues my significant other got an offer to work at one university in California as a postdoc. Of course, I want to follow to keep us together. Therefore I will drop my current Ph.D., and try to find another one in California (Riverside, Irvine and maybe Southern California would be good options given my research experience and interests). 

In summary, my profile:

I'm in my early thirties, having five years of experience as Software Engineer, with a dropped out (soon) PhD in CS (GPA of ~3.3, first-year courses, TA for one semester) at a top Asian university, a Master's Degree by research in Neuroscience ("GPA" 2.54 out 3, my country scale) and a 3 years Degree in I.T ( "GPA" 6.8 out 10, very low). I have four publications in total as follows: two articles in neuroscience journals (first author and second author, impact factor around 3.5). and two papers in computer science conferences (I would say Database conferences, but they also accept NLP/ML papers, my case) with one short paper first author (international conference held in USA, Core ranking: A) and one second author in a workshop paper (international conference held usually in Europe, core ranking B). I want to apply to Ph.D. programs in Computer Science or Computational/Cognitive Neuroscience. 

My issues:

I heard back from one university that I could combine my 3-year degree with my Masters to fulfill a 4-year American bachelor requirement. Has anyone tried it before?

Given my low undergrad GPA, my plans are to voluntary work with some professor/postdoc/grad student in one of my desired universities/labs. As I will follow my S.O, I will be living in the US. We are ok to give me one year off to prepare myself for the next year applications round and upgrade/bulk my CV while there. I aim to get at least one recommendation letter from someone working at my desired program (the other two, I would ask my master's advisors) during voluntary working there. Is it often to people aiming to overcome limitations such as low GPA to voluntary work in labs to get letters of recommendation and research experience before applying to any Ph.D. program? Do you guys think that could sound as good plan? Of course, in the meanwhile, I will also study to get a good GRE score.

Could you guys give more tips about things that I could do during this year off working to improve my academic CV?