Postgresql – Create smaller row from alias and preserve column names

Using Postgres:

SELECT users."name" AS "name"
    , array_to_json(array_agg(sites)) as sites
FROM remodel.users AS users
JOIN remodel.user_sites AS user_sites
    ON users.id=user_sites.user
JOIN remodel.sites AS sites
    ON sites.id=user_sites.site
GROUP BY "users".id
;

currently produces

"Toby";"[{"id":1,"name":"Village","created":"2015-08-10T15:22:36.622298"},
         {"id":2,"name":"Manor","created":"2015-08-10T15:22:43.614551"}]"
"Amy";"[{"id":3,"name":"Park","created":"2015-08-10T15:22:48.810872"}]"
"Anne";"[{"id":2,"name":"Manor","created":"2015-08-10T15:22:43.614551"},
         {"id":1,"name":"Village","created":"2015-08-10T15:22:36.622298"},
         {"id":3,"name":"Park","created":"2015-08-10T15:22:48.810872"}]"

however I would like not to have the "id" field in the JSON output.

changing the sites selection to

array_to_json(array_agg(row(sites."name", sites.created))) as sites

causes the fields to lose their names

"[{"f1":"Village","f2":"2015-08-10T15:22:36.622298"},
  {"f1":"Manor","f2":"2015-08-10T15:22:43.614551"}]"

and attempting (what would be a horrible) sub selection

, array_to_json(array_agg((SELECT "name", created FROM sites))) as sites

understandably throws an

ERROR: relation "sites" does not exist

And removing the id with a select in the from clause prevents joining the tables.

I'm looking to preserve the column information as well as I can, not just for conversion to JSON but for inclusion in much larger and complex queries, so performing the array selection without using JSON is preferred.