Technically I think you will be fine to install windows 7 in your laptop, the hardware in your laptop probably is not that new and designed just to work with Windows 8.
In every new laptop, the hard drive usually has 1 hidden partition where they store the Windows recovery software and also when the first time you boot your laptop, they usually advice you to create the recovery disks, just make sure you do that before installing windows 7 so if for any reason you cannot get your laptop to work with windows 7, you can always reinstall windows 8.
Also, go to HP support website, look for Windows 7 drivers for your laptop model.
In the past, I used to help friends to install or upgrade Windows, I use a third party software called "Driver Genius Pro" and I ran it after re-install/Upgrade and it would find every missing drivers that need to be installed so I don't really need to go to the manufacturer website to dig out for drivers, save me time.
Hope it will work out for you.
Again, to answer the above question, Driver Genius Pro can back up the drivers that are currently installed in your system but you don't really need them because when you install Windows 7 or 8, those drivers will be installed automatically thru Windows Installation and after that, if the drivers need to be updated, Microsoft will update it thru Windows Update.