I don't think I would have the nerve to invest in a relatively unknown cryptocurrency such as PIVX for the "long term" which you say is 9 months to 18 months. I think I would be freaking out in 10 days. I wouldn't be able to sleep at night.
Please tell us, what did you find in your research that makes you think that these coins have an active development team working on the coin?
This is where the messed up screenshots formatting would have helped.
What I found was what is in the screenshots at the top of the page, as of 9 days ago, their was a android wallet released for the coin. This would imply an active development team within the past 10 days :)