It is impossible to say exactly when those backlinks will start to give your sites link juice.It depends on how quickly Google index those backlinks.So you need to wait and in case of link building don't be desperate.

There's a difference between google crawling your links and actually indexing them, so just because they've been seen doesn't mean they've been counted, a lot of these low level links need to be pinged multiple times before google will count it, even then they don't tend to hang around long, many get de-indexed, I really only use these types of links to link to my contextual authority links, the links that actually move you in the serps, otherwise links with no surrounding unique relevant content just ain't what they used to be.

You bought relatively worthless backlinks. I hope you didn't pay much for them because if you did, you got screwed.

.edu backlinks are no better than any other backlink. If someone is selling .edu backlinks, they are most likely on PR 0 or PR n/a pages and probably are littered with 100 or more backlinks, making them even more worthless.

Social bookmarking carries almost no ranking value whatsoever. Social bookmarking is good for getting a page indexed, and sometimes those links can bring some traffic, but they carry very little ranking value.

If by forum backlinks, you mean forum profiles... Well, it will take anywhere from a few weeks, to a few month, to never for search engines to find those links. Many forums do not have publicly viewable profiles, which means they will never be found.