No. Of course not. Someone who can't read due to mental disability isn't morally inferior to someone who can and does.
Sure. I'm answering it by another measure. Killing is, ceteris paribus, morally inferior to not killing. I'd argue a psychopath is henceforth morally debilitated despite it not really being their "fault" that they're born without empathy. This, in turn, helps me conclude that a murderer is, in fact, doing wrong.
Same here. Someone who can't read isn't inherently less morally capable than someone who can. What reading gives one is the capacity to gain a better understanding of ethics and morals. So I'd guess folks who read books are, on average, more intelligent and at least seeking to conduct themselves in a more moral fashion than someone who doesn't. But that doesn't make spending time reading morally superior to some other activity.