Are there recent estimates of Kuiper belt mass?
Surprisingly, I also have not been able to find any generally recent (5 years or less ago) information about this topic. 

I did find a research paper from 2007 (Here). You may want to check out page 11 in Section 4.3. It states that the maximum mass of the Kuiper Belt is 0.1 Earth masses. They also talk about how it was estimated and such.

I haven't been able to find anything else besides Wikipedia articles (which you probably aren't looking for). 

Very strange how there hasn't been a lot of research on this. An intriguing topic, I must say.

That's all I could find... Hope that helps...?