White Center's been hipster central for a good ten years at least. Though it's not as crime ridden as it used to be, property crime is still high due to the milieu that progressives tend to indulge wherever they go.

As for the new chapel further south, I'd guess it will bring in some curious locals in addition to the longtime trads who'll make the trip from out of town. The GI Bill generation that formerly lived in that neighborhood has died out, and their heirs mostly refuse to put up with the extremely noisy SeaTac flight path. Lots of recent homeowners are from Asia and Central/South America, culturally conservative compared to the city as a whole. Thus, MHR might very well attract some NOM Vietnamese and Filipinos and even some dissatisfied Pentecostals, the children and grandchildren of those lost to V2. (P.S., check out some of the surnames on those Mass intentions in the bulletin. Also Google Maps has photos and reviews going back several years, so the chapel's been around for a while.)

Here's the website, (and they also link to the Mount Vernon location further north in their Resources list). Note too that according to the bulletin they have Mass daily and twice on Sundays, and their website encouragingly says: "A 2nd Collection is taken on the First & Third Sundays of each month. This Special Collection will go toward remodeling and building expenses."

Good to know, thanks. Yes, the progressives there (and everywhere in Seattle, except maybe the wealthy neighborhoods) certainly do tend to indulge wherever they go. 
From what you mention above, it seems that the chapel will grow further over the next few years. In looking over their bulletin, it appears that they don't red-light other Latin Mass venues, but they do red-light the novus ordo, which is a good thing of course. 

In looking at their second location in Mt. Vernon, it looks like a beautiful old church, and I don't recall ever noticing it in Mt. Vernon, being somewhat familiar with that town. It's good that they are located on the east side of I-5, since Mt. Vernon is prone to flooding from the Skagit river.