I was watching some anime and realised that some character says わからねいし instead of わからないし. Is this just a slur kind situation where they change it so it's easier to pronounce, like how native speakers often say してんの rather than してるの. (Also this is just my understanding might also be wrong) One mor...

I'm a reader and also a starring author/artist, and I wanted to ask if it's okay to upload one manga in many different apps? I mean, I haven't seen a single manga that I've read that was posted in another app, so I thought that maybe it's be illegal to post a manga in alot of different platforms?