I'll answer the first BQ before the original question because some of the terms from that question are used in the original one.
I've never heard of "wotaku" before now, but I looked around online and it seems to be the same thing as Otaku. Just a mis-romanization of the word. A Fujoshi is a female Otaku (it means "rotten girl"), and is usually used to refer to girls who obsess over yaoi though it can mean other obsessions as well. An itasha is a car covered in anime stickers, and a hikikkomori is a shut-in who never really leaves their house and stays inside all the some. Hikikkomori are NEETs, meaning they're unemployed, not in school, and not in any kind of training or military service.
Otaku have a very bad rep in Japan because they are associated with being Hikikkomori and because they are associated with several murderers in the past. There have been a number of famous incidents in which men have kidnapped, raped, and/or murdered young girls and when police later searched their homes they found a ton of anime paraphernalia. Otaku are also so highly obsessed (not just with anime, you can be an Idol otaku, computer otaku, military otaku, train otaku, and so on), they put their obsession before their jobs, their family, and their well-being. Not all otaku are like that but that is how they are perceived by society.
BQ2: A lot of singers, dancers, and the like cover their faces when doing anime covers. It keeps their identity a secret so people don't recognize who they are. This is beneficial for a lot of reasons, such as preventing stalkers or preventing people from tracking them down in real life, or if they have a professional career that necessitates they present themself in a certain way their reputation isn't ruined in real life.
BQ3: You could be, or you might not be. If you're obsessed with anime you'd probably be considered an otaku. If you just watch the occasional episode or two you're not. There are also a ton of other factors about your behavior but it basically boils down to (especially outside of Japan): if you consider yourself an otaku, you are one. If you don't, you're not.