I just gave it a spin as well since that reference to EVE_OPT_CENTERY and it just works for me either.
EVE_cmd_text(120, 100, 28, EVE_OPT_CENTER, "Lala\nFoobar");
EVE_cmd_text(120, 160, 29, EVE_OPT_CENTER,"one two\nthree four");
And the other options like EVE_OPT_CENTERX, EVE_OPT_CENTERY, EVE_OPT_RIGHTX or EVE_OPT_RIGHTX|EVE_OPT_CENTERY are also working.
This also does work:
uint32_t args[16];
args[0U] = 1234;
EVE_cmd_text_var(120, 220, 29, EVE_OPT_CENTERY|EVE_OPT_FORMAT,"log:\n%d%%", 1, args);
It does look a little strange with an UTF-8 font though, the spacing between the lines is off, probably because the height of the characters is too high.