Glad to see a person taking an interest in the UC system As a Californian, this makes me very happy lol.
UC English departments are usually strong and renowned, so it's supremely important to determine the kind of intellectual fit you're looking for in each UC. Definitely check each UC to see what kinds of their work their professors are doing and what their strengths are. The competitiveness varies from campus-to-campus, but it is safe to assume that PhD in English admissions across the UC system are going to very competitive. Some of the UC graduate divisions have average statistics posted on their website, but they don't exactly break them down by the specific year for some metrics. And remember, these are statistics, and are never going to be indicative of your real chances in a UC PhD program in a given year. From scouring the graduate division websites, I've found three of them that have some data on how the admission numbers look like.
UCLA English: https://grad.ucla.edu/programs/humanities/english/#program-statistics
UCI English: https://grad.uci.edu/assets/images/Academic Data/phd data/EnglishPhD_Academic.html
UCSB English: http://www.graddiv.ucsb.edu/documents/stats/ENGL_Grad_Profile_Final.pdf
These statistics do not replace looking into departmental websites (and the statistics are averaged across multiple years as a disclaimer). It's definitely sage to keep in mind the advice that has already been posted here. Check each UC English site to see what each department might particularly look at (some UCs may want more language experience, some are fine with 1. Not every UC has a traditional English department, UCSC and UCSD come to mind), but it's a safe bet to work under the operative that all aspects of the application must be strong. Some of the UCs carry informal goalposts (such as having a 3.5+ uGPA in your Junior and Senior years to be competitive, but this may only be strongly salient if you are a BA-only applicant) but ultimately, demonstrating an intellectual fit with each UC school is what will help your application the most. With that, I definitely agree that the Writing Sample and Statement of Purpose are the most integral aspects of the application. They are that documents that will demonstrate that you can do doctoral work and also show a research trajectory that can be supported by your chosen department.
Funding... Definitely carefully read the funding section of each department website to know what you're getting into. I can only speak specifically for UC Irvine but fees are partially covered. On Fellowship, I have to pay about $770 in fees. On TAship, I have a partial fee remission and I'll pay $473. This varies from UC to UC so if you do end up getting offers in a future cycle, check and double check your funding offers carefully to see if fees are covered. In general, a UC school will offer a living stipend (UC data is posted on the thread that mandelbulb linked) as well as tuition remission and health insurance.
Good luck with your application!
you can find out various funding packages and compare them with other english/literature PhD programs here to get a feel for whether they're competitive:
as for how each program funds their students, it depends on a few factors, but it seems you're either funded with a fellowship or through a teaching assistantship. these usually include full tuition remission and a living stipend; fees are typically reduced, but they may or may not be covered completely depending on the UC i think.
as for your application, i'd check the individual programs to see if there is any language emphasizing whether they take any specific element of the application into more consideration than other elements. however, there's been general consensus that you need to focus on every element of the application and make sure each one is as good as you can make it. for example, if you take the GREs and your score isn't as high as you wanted, you can either choose to retake it if you think you can do better (thus making it as good as you can) or choose to spend that time elsewhere (because the score is as good as you think you can get). we've heard that in general people tend to regret spending the time and money it takes to get a better score. if you have to focus on just one or two elements of your application, my advice would be to focus on your statement of purpose and your writing sample. if you can only focus on one, it should be your writing sample.
good luck!
