This is a followup question to Touchpad not recognized on new Ultrabook

In that question, asker had trouble with the trackpad not working on Samsung ATIV Book 9 2014 Edition (NP930X5J/NP940X5J) with Ubuntu 14.04 LTS. (I am having the same exact issue.) The accepted answer said that it is a kernel bug and that the final version of 3.15 kernel will contain the fix. The answerer linked to kernel bug report https://patchwork.kernel.org/patch/4096321/

I read news that the stable 3.15 kernel was released a few days ago on 8-Jun-2014. I am hopeful that it has the fix for this issue!

Question 1: Does the stable 3.15 kernel indeed contain the fix (kernel patch 4096321)?

Question 2: What is the next Ubuntu release that will contain this kernel (and hence contain the fix that I need)?

Question 3: If I can't bear to wait until the next Ubuntu release, then what is the next Ubuntu test kernel (I'm assuming from kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D but correct me if I'm wrong) that would have the fix?

Question 4: If I want to install the test kernel that is the answer to question 3, can I do that safely without leaving 14.04 LTS? I really want to stay on an LTS version of Ubuntu. I'm not looking to upgrade Ubuntu every 6 months. I just want to make my trackpad work and then not make any further changes to my system for a few years (except automated updates, of course).

Thanks in advance!

PS. I'm new to Linux/Ubuntu so forgive me if some of my questions are badly asked.

Update:

Thanks for the answers. I finally upgraded the kernel to one of the stable 3.15 versions from here (delay was mostly due to me being afraid of the unknown, particularly of breaking my computer). I'm half-happy to report that the touchpad now half-works. Specifically, it works after computer startup, but stops working after suspend+resume.