Fame is of course an amorphous thing - one person's "household name" is another person's "who's that", depending on demographics (perhaps most amusingly demonstrated on Twitter a few years ago, when Bon Iver won a Grammy, and the R&B fans hoping a Beyonce would win that year were terribly confused, wondering why Bonnie Bear had won). Nonetheless, the way that magazine articles profile the band can tell you a lot about how a band want to be portrayed (to a certain audience) and what the journalists think is the most interesting things about the band - e.g., who the stars are, who the most famous members are.

A brief Googling finds five profiles of the group from around the 1989 release of Straight Outta Compton: one in Rolling Stone, one that was originally in the shortlived British magazine Sunday Correspondent, one in LA Weekly, one in defunct British music magazine Melody Maker, and one for BAM Magazine.

Rolling Stone's article largely focuses on Ice Cube as the 'twenty-year-old writer behind much of N.W.A.'s lyrics', with a quote each from MC Ren and Eazy-E. The Sunday Correspondent article is longer, and heavily based on an interview with Ice Cube, from which it quotes extensively; there's also a quote from Eazy-E. The LA Weekly article is structured around Eazy-E's entrepreneurship, with reasonably extensive quotes from MC Ren and Ice Cube. The Melody Maker clearly only interviewed Ice Cube, and mentions Eazy-E a fair bit. BAM magazine had an interview with Ice Cube and Eazy-E.

The profiles also have a tendency to list the members, and the order of those lists is indicative: after mentioning Ice Cube and MC Ren, Rolling Stone list that the "other members are Eazy-E (Eric Wright) and producers Dr. Dre (Andre Young) and Yella (Antoine Carraby)". Sunday Correspondent says that "Ice Cube arrives at his publicist's wooden-frame house in south central looking quite unmoved by the stir NWA has caused. The group's founder, Eazy-E (whose real name is Eric Wright), production specialists Dr Dre (Andre Young) and Yella (Antoine Carraby), and the other main rapper, MC Ren (Lorenzo Patterson), all still live in Compton." The LA Weekly and BAM profiles don't obviously list the band members in this way, but the Melody Maker list them as "Ice Cube (real name O'Shay Jackson), Eazy-E (Eric Wright), MC Ren (Lorenzo Patterson), Dr Dre (Andre Young) and Yella (Antoine Carraby)".

So, yes, I'd say that MC Ren received more prominence than Dr. Dre in the initial flurry of publicity around the group; Dre was largely portrayed as a backroom boy rather than a personality. However, Ice Cube and Eazy-E were very clearly seen as the biggest personalities/the most famous in the group. After Ice Cube had left to go solo, and the group released 1991's Efil4zaggin, there was a further round of profiles which obviously could not rely on Ice Cube's soundbites. The Rolling Stone profile puts more focus on Dr. Dre than Rolling Stone's 1989 interview did, but only because of the charges that he had beaten up a female TV host; otherwise the profile focuses a fair bit on Eazy-E and MC Ren. In a 1991 Spin interview, the group members are listed in the order 'Eazy-E, Dr Dre, MC Ren and DJ Yella', also suggesting a new prominence for Dr. Dre. Of course, by this point Dr. Dre was a more prominent member of NWA, having taken over some of Ice Cube's previous rapping responsibilities - it had become somewhat harder to forget about Dre.

As to whether Ice Cube's 1991 song 'No Vaseline' reflects the prominence of the group members, it's fair to point out that Ice Cube's level of beef with the other members may also play a role. It's also worth pointing out that Dr. Dre had left N.W.A. in April 1991 (for similar monetary reasons to Ice Cube, just somewhat later), and 'No Vaseline' was released in October 1991. Dr. Dre was the one who had called Ice Cube 'Benedict Arnold' on the Efil4zaggin track 'Real Niggaz', and so he had to be dealt with on the diss track, but as Dr. Dre had also become a Benedict Arnold by this point, there wasn't much point in spending much time dissing him. Ice Cube's beef was primarily with Eazy-E, who was the part-owner of the record company NWA were on; to the extent he focused on MC Ren on 'No Vaseline', it's because he clearly felt he was Eazy-E's toady.