write a "macro" to launch multiple terminal windows with one icon
I would make each script be saved to a plain text file and you can name them 1 and 2 and 3 and 4 and put them in a folder.

When you name a plain text file abc.command, clicking it runs the script.

I'd also use https://brew.sh to install mongodb so you can just use brew services to run that at launch. It's likely lightweight and you could have a "restart" script in case the demo goes south.

Also - teach your sales people, this is an easy thing to understand and imaging how much better they can sell when they say - I know tech and I know how to run and manage not only the product we're selling but own the demo requirements. Good luck in your venture.