Do you mean MSXML 4.0 SP2 and not MSYML 4.0 SP2?
MSXML 4.0 is obsolete and has been replaced by the latest version 6.0, see
https://en.wikipedia.org/wiki/MSXML.
As for your question concerning deleting / uninstalling both types, the Visual C++ files were most likely installed as part of some other 3rd party program installation that you may have installed in the past on which they have a dependency. If you remove those Visual C++ program files it most likely wont hurt your main system windows system files but the 3rd party Apps, whatever they may be, may fail to run. See
https://en.wikipedia.org/wiki/Visual_C%2B%2B
Likewise, the MSXML 4.0 files will be in the same category as the Visual C++ files.
In any case the 56 Mb size you quoted, assuming correct, is fairly small for disk usage and as such you could just leave them as is.