I would like to know where the names for the sedras come from (who named a certain sedra Balak, Emor etc.) and if there is any meaning associated with the naming (as the Lubavitcher Rebbi seems to indicate). In other words, did it just become convention over time (and if so when was it 'canonnized') or did some person(s) assign those names with specific intent ?
Rambam (Rambam Hilchos Tefilah 13:1) refers to parshas Metzorah as"vezos tehyeh Toras Hametzora" and refers to Parsha Bamidbar as "Bimidbar Sinai" among other parshas. Similarly, Sefer Hachinuch refers to Mishpatim as "ve'Elah hamishpatim" parsha Bo as "Bo el Paro" and even adds a break in Mishpatim to have another Parsha! (The minhag of Barcelona was to sometimes divide Mispatim into 2 portions so that Parsha Metzora is read before Pesach. That is why sefer haChinuch has a parsha called "Im Kesef Talveh" (see Sefer HaChinuch, Machon Yerushalayim edition, pg 308 footnote 1))
It is pretty clear that the standardized naming of parshas is of more recent vintage, perhaps when calendars with printed weekly parshios became popular.
At the same time, perhaps one has the right, as some do, to interpret the parsha names homiletically since "minhag Yisrael Torah" and the Hashgacha peratis that directs Israel through the years of exile has directed us in this direction. This approach is found in Hassidic literature in other contexts as well such as homilizing the driedel and its spin.