I have been on the hunt for a solution to how the LG lockscreen handles notifications. I hate how you cannot just double tap to open the notification like you can on the AOSP lockscreen. After trying damn near everything I could find, I came across Floatify. I remembered using it back in the kitkat days and forgot about it. Seems the dev is still active, even has beta group on G+ with an update yesterday. It can be used with the stock lockscreen, which is something I prefer over replacement lockscreens and handles everything very well, with all sorts of features. The pro-key is 2.50 but with everything available, its easily worth it.