If you're not using it you can uninstall Outlook.
I uninstall Calendar too, I don't think Windows is ideal for things like this, I like "webmail" and I don't use any calendar software anyway.
>repo of freeware Windows apps
Almost all freeware has always been for Windows, "safe" has always been the elusive thing you can only gather from experience.
I have a tendency to trust majorgeeks.com but I would still think some malware could occasionally be lurking in some downloads if you are not careful.
For the longest time there were only what is now called Windows "desktop" applications, still seems like the real thing compared to the Apple-inspired "Store" apps, which have that amateurish feel.
So far I have no need for the MS Store but I don't uninstall it "just in case". Still haven't used it though, it's not easy finding software or even hardware that's "worth money".
Edit: Also give an idea of some basic things that you need addressed!