I find that to be a hair-splitting distinction rather than a meaningful one. But even if we agreed on that, well: Gavin McInnes has defended Holocaust deniers, supports the Muslim ban, and pushed white genocide conspiracy theories, as well as saying, "I don't want our culture diluted. We need to close the borders now and let everyone assimilate to a Western, English-speaking way of life.". Cernovich has peddled anti-Semitism. Laura Southern is openly racist, supports white supremacist groups and worked to prevent ships of migrants and refugees from landing in Europe, and she's apparently currently working on a "documentary" pushing white genocide conspiracy theories. And Milo has openly pushed nazi rhetoric over and over and over again.
So, no, going by that list, the distinction is trite and meaningless.
Oh, it's absolutely a hair-splitting one, but I've been attacked by enough alt-righters to know what's non-negotiable with them and a lot of that is beliefs these people have. Gavin goes back and forth on this from what I've seen and I'm not sure if he's a poorly-veiled crypto alt-right or just genuinely stupid and unable to express his beliefs well (or both), so I won't argue much on that one, but at the very least his support of Israel and gay rights makes it hard to call him a deep alt-right. Cernovich is a "dirty race-mixer" to the alt-right, and with miscegenation being one of those non-negotiable things, I wouldn't categorize him as one even though literally everything else about him fits. Southern is basically a female PJW that actually leaves her house from time to time, but the rejection of white nationalism makes it hard for her to be straight up alt-right as well (also the alt-right thinks she's Jewish). Milo I've gone back and forth on, so I won't harp on it as literally the only thing holding him back from it is being a gay Jew (as self-hating as he is).
I made a sort of tier list in the Leftist YT thread a while back, but it probably needs editing at this point.