Reward cards are for people who can demonstrate to the lender that paying them the rewards is "worth it", and the lender comes ahead in the end.
Let me step back from just answering your question and understand what you are trying to do.
First, stop doing what you are doing right now. No further applications as you have reduced your chances of getting unsecured credit by having a lot of hard hits to your report.
I assume you have a SSN, and in that case what you are doing is digging a deep hole to put yourself into the next year unless you have a job at hand (to justify a debt-income ratio that a lender will look at before approval).
Read this and ask questions: Ways to establish credit history for international student
Tell us more about your background: esp. if you have a job, how much credit you are seeking and what made you decide applying for rewards cards was a good idea to begin with.
Updated after OPs edit:
Your question has been answered already: the answer being "Yes". I trust the answer and the person behind it.
However, I know where you are coming from, and what you should focus on is establish a strong foundation for your credit. In that light you shouldn't be asking about rewards card.
Rewards will come (I am told) but the time's not now. The reason is embedded in your own edit:
For the record, I'm an incoming PhD student on a fellowship with an
expected annual income of $30k for the next 5 years. I wanted to apply
for reward cards since some of them were available and I wanted to try
them out (but I'm ignorant of the bigger picture as I know little
about credit cards)
The lenders have no metric about your expected annual income: they can see the data in a W2, in a 1040 or similar.
Anything else is up for speculation; even your expected salary on a contract: if your project gets shelved or your advisor gets fired, you no longer have the money. If the lender gives you a line of credit you are then likely to use it up and then have a hard time paying it back.
Establish strong foundation for your credit, focus your efforts there for now.
If you have done less than 3 apps recently, see if you get a secured credit card.
If you don't get approved, it looks like you can have your parents to help you out? Add yourself as an authorized user to a BofA card they own. I know BofA reports the authorized users on their cards.
You can try a student credit union: I use http://www.schoolsfirstfcu.org/. They rock. The fact that my professors also have accounts there and I often go in with them when I have a favor to ask from the CU might bias my feedback, so do your own research.
You are a smart guy, put that brain to use :-D
Best of luck!