You are correct. The articles are not sorted at all, rather, they are displayed in the order which the feed publisher has provided them. If you would like to support the implementation of date sorted articles from multiple feeds, you can make a donation. :-)
Regarding no-index, there are 2 types of no-index according to wikipedia: http://en.wikipedia.org/wiki/Noindex
The first type is the standard page header meta tag which you would define on your page meta settings in WordPress. Syndicate Press has no control over this type of noindex setting since the page meta tags are controlled by WP when the page headers are sent to the client. There are lots of plugins which modify the headers sent for specific pages/posts to include the noindex meta tag.
The second type of no index is an html block tag that is only supported by a very limited number of search engines (primarily the russian search engine Yandex according to wikipedia). Syndicate Press could implement this functionality, but it would only apply to whatever search engines honor this block tag.