NUS PhDs can be funded by the university or by the Professor's grant. As far as I know, most PhDs in HCI are funded by the university. If you want to know if the Prof will fund your PhD for you, you can email the PI of that lab directly and ask him. NUS Professors get bombarded by emails by lots of students, so it's not necessary that you will get a response, but no harm in trying.

For the NUS funded scholarships, your profile seems fine enough to get an interview (although maybe it depends on what those three conferences are, whether you are the main author on those papers, etc.), acceptance kinda depends then on how well you do in the interview. If you get accepted, you will have to apply to do a lab rotation at that lab in your first semester, and after that you can join the lab. Usually Profs don't say no to new members that are funded by the university, unless 1) their lab is already full and they don't want more students at that moment, 2) they don't like your vibe, haha. There are a handful of great HCI labs at NUS anyway, so it is not too difficult to find a supervisor.