I am trying to add a new text component in the InList, can I do it? And can I change the size/color etc of that?
No, you can’t add or modify parts of an inline list other than what settings are already provided. Components, such as a text component can only be added to a Details Style layout screen, or the details screen when viewing a particular item in an inline list.
If you want to start changing colors or or sizes, you will have to start manipulating the CSS that controls that. There are several posts that talk about doing that.