Hi I am not very familiar with program but I can see that one of your questions is about application fees. Universities offer a lot of fee waivers and emailing the grad chair of the department you are interested in usually gets you the waiver or you can apply through FAFSA/financial hardship if you are a US citizen. I got fee waiver for 90% of the grad schools I applied for. Also, seems like you like the internship since you wrote a lot about it than actual grad schools. However, I am not very experienced in your field and so can't really help make the decision. Although, I don't think they will down on you for deferring/rejecting to pursue research in the field. Good luck !