I have many friends at these places, so I could chime in.
For Uber, some of them are already looking for places in Mission Bay(near their new HQ), Alameda, and some even Hunter's point. But these guys are currently money hungry (their base salaries are under market price except those who joined after 2015 who got much less equity), and most younger ones (which is vast majority) can't buy a house yet. When they go IPO, I'd guess a big change in market.
AirBnB - I'd expect they would go to Mission, Hayes Valley, even Potrero Hills. These guys are even younger than Uber employees (the place is filled with folks who can't drink) but the company culture is fairly hippie. I don't expect them to be taking caltrain anywhere..
Snapchat is a bit more mature, at least in SF office. They have been hiring in a stealth mode, targeting mostly well-established places (Google, Facebook, ..). Senior members already own houses in Southbay, and some are commuting to SF from places like Los Gatos. I don't know if they'll move to SF due to their kids going to schools in Southbay, but it surely won't last forever.. But a bit younger ones (late 20s~ early 30s) may or may not own homes in South bay. If they do, it'll be a small condo / THs in Mountain View (94043 ish), Palo Alto (near 101/Oregon). These guys will go up to SF if they go to IPO, or mayyybe San Mateo near the caltrain.