Re: South Boston Development
Yes, most of this "small-scale" development in South Boston is occurring on East and West 1st, 2nd and 3rd Streets. So north of Broadway heading toward Seaport and downtown. I believe they rezoned the streets to permit residential a few years back. Lots of nimbys keep showing up but no proposals seem to have been shut down as a result.
As for linkage, it looks like the main arteries between the two are A Street, D Street and Summer/L Street. D Street has the most activity between the private developments and convention center hotel expansion. A Street is improving but is still plagued by the channel-side parking lots that Gillette apparently owns and the USPS lot across the street. No idea what the development plans are for those.
The Pappas family also owns a ton of land east of the convention center that is apparently being put up for sale/redevelopment. A CRE trade journal had an article on this a few months ago, but haven't seen anything since.
For a decent view on how it all looks in real-time take the South Boston Bypass road from 93 through and into the Seaport. Not only do you get a great view of downtown, South Boston and the Seaport, the signs identifying the bridges you travel under are London-style.