Keep XAMPP & Install WAMP

Question

I am using Windows 7 and I have XAMPP installed. In Git Bash when I type php -v I get PHP 5.6.15.

I need newer version of PHP because I am using Composer and I am unable to install packages that require PHP 7.1.

I know that one way to solve this is to backup projects, uninstall the current XAMPP and install the latest one (with PHP 7.1)... but I would like to avoid this (if possible) because there are a lot of project files in C:\xampp\htdocs and many MySQL databases...

So, I am thinking about keeping this XAMPP and installing WAMP with the latest version of PHP, but I have a few short questions.

PLEASE NOTE THAT I WILL NOT USE THEM AT THE SAME TIME - I don't plan to start Apache from both XAMPP and WAMP at the same time, I just need to be able to run some of my projects when needed... if it's an older project from XAMPP directory that requires PHP 5.6 - then I'll start XAMPP and use its Apache/MySQL. If I need to create a new project that requires PHP 7.1 - then I'll stop Apache/MySQL from XAMPP and start WAMP...

QUESTIONS:

1) Will this work at all? Is there any reason why I should avoid doing this? (keep XAMPP and install WAMP)?

2) If I keep my XAMPP and install WAMP with, let's say, PHP 7.2 - which PHP version will run on my computer, 5.6 or 7.2? In Git Bash when I type php -v - which version will be displayed? Which version will be used by Composer?