It varies. Sometimes you can find uncensored manga on Mangadex, but it's not a guarantee for all series. It really depends on the uploaders and the availability of uncensored versions.
Mangadex might have uncensored manga. But it's important to note that the presence of uncensored content can change over time and is subject to various factors such as publisher restrictions and site regulations.
Mangadex.org does offer light novels. However, the selection might not be as extensive as some dedicated light novel platforms. But you can still find some popular and interesting ones there.
I don't think so. Usually, if they had an app, it would be pretty well-known and easy to find through a quick online search. But I haven't come across any info about it.
DC indeed has a comic app. It provides a user-friendly interface and regular updates with new releases and classic comics. It's a great way for fans to engage with the DC universe on the go.