Once you install Windows 7 the Windows 8 drivers for your devices will no longer beavailable - you will have overwriten them as part of the install process. But I would expect Windows 7 to identify and install the necessary drivers for your devices. Before in stalling Windows 7 please make sure you burn a set of Windows 8 recovery disks - your pc should come with a utility to do this. Some time in the future you may well wish to recovery your Windows 8 system.
You will run into more problems when going backwards to Windows 7 as all OEM, UEFI machines (as most are these days) preinstalled with W8 will have Secure Boot enabled. Secure Boot is an advanced security feature that prevents badguys from circumventing the installed OS with another OS.
While W8 has a fairly steep learning curve, it is a much better OS in terms of security and performance. And while W7 is an excellent OS, I would urge you to stick with W8 as that will carry you further, and more securely into the future.