How to best fill in the gap year before applying next cycle?

[FlyingGoldFish]

I applied in my senior year without hope as my stats weren't good, but I tried to take a shot to gain some experience. I applied to about 4 schools for chemistry and biochemistry programs and got all rejects, which I wasn't too surprised since I wasn't finished taking major courses. I'm not too proud of my stats: 3.2 GPA, 3.1 major GPA, 143/154/4.0 GRE, 2.5 years of research experience (both experiences in synthesis and biochemistry research), and no pub. I graduated already, and I'm trying to apply again this upcoming cycle around October-December. I have about 6-8 months before submitting my applications, so what would be the most productive way to fill this gap?

Some things that I'm already working on are:

- I am currently working on GRE, and I'm also planning to take the Chemistry GRE in September. 

- I talked with my research advisor, and we can work on a paper to submit for one of the research I did. So, I might possibly be a second-author for the paper. 

- I am also trying to replenish the LORs. The research advisor said he wrote a strong one before, and he would update it more for this one. I also have different professor writing LOR for this time who is very understanding and knows me well. I'm currently looking for 3rd recommender, but it's in process for now. 

- I am trying to find a research position of some sort to gain more research experience. I'm not sure if that would be helpful at this point, since I just have months left. 

- I am getting the feeling that doing Masters to recover my GPA won't be worth the chance, since it is another investment, and I have a set goal that I want to go for PhD for academia path. 

I've been seeing some good constructive advice here, and I would love to hear back thoughts and comments on my situation. Thank you

[Meems]

Yeah, publications would extremely help. Try to work as a research assistant and put in as work experience on your CV. 
If you can secure two papers or three it would be great, even if you at least publish one and get another one in the process of submission, then you can include it on your CV and put at the end "To be submitted"