Long story short hun, going purely by the colour schemes you've described, then the answers to the various combinations would be as follows:
Plain black skirt and plain (I assume?) black top: This would likely work because there's low contrast between the two colours. This would also be kinda boring and obvious though, so if you're trying to be striking then this would dampen your impact.
Plain black skirt and grey with white stripes top: This would likely not work because it would be too contrasty between the white and the black. I'm assuming either a mid or light grey though. If it's a very dark grey then it could be made to work if you have some complimentary accessories to balance it.
Patterned red skirt and grey with white stripes top: Again, this is a very contrasty setup that likely wouldn't work. You'd have 4 different colours (red, black, white and grey) that are quite strong and would be competing with each other for attention. Depending on the amount of each, this is probably the worst colour combination (grey and red in particular tend to always have a lot of issues with each other in my experience)
Patterned red skirt and plain (I assume?) black top: This is probably your best combination. The black in the skirt would reflect the black of the top, tying the two parts together. The red adds a strong accent, and even though there may be a lot of it, the black will take a back seat to it because of how black works with strong colours (this is why black and red are often a really good combination).
I was going to try and show the colour schemes but can't find a good way to represent it lol. In any case, I hope that helps hun
<3 *hugs* <3