2. Most "good" girls would not date a guy with a tattoo, especially visible. Nearly all parents would disapprove vehemently. I wouldn't expect to have any type of relationship with her family and most likely if she's close to hers at all, she would have to make a choice. You'd think it's so barbaric to disown or shun a daughter for who she dated but it's actually not that uncommon. Think 1950's and a white woman brings home a black man to her family.
3. People would actually be more scared of you if you dress well with tattoos. You would certainly be taken for a mafia member. While most Westerners think it's funny, they are still very much active here. Think 60's Vegas or 70s-80's East Coast where people actually did get roughed up and killed, not appear on reality TV shows.
It won't mean you can't find a gf, wife or friends but just like finding a job if you had to, you limit yourself a lot since it's an extremely conservative society. At least it's not Saudi Arabia.
I've always wanted a tattoo but my wife said if I get any, even a tiny one of a cartoon character, she would divorce me and she lived in the US for 15 years. Not a joke by the way, most Japanese people don't joke.
To put it succinctly, it would be very much like taking a time traveling DeLorean to the US in the 1950s. There are onsens that are private for couples or families which you could go if you keep everything covered but even if there is no policy written, if noticed at any gym, bath or onsen you would be asked to leave. If you are not Japanese/Asian, you wouldn't be taken for a yakuza member however the general public would think you are part of the criminal element and avoid interaction even more so for being just being foreign. It would be quite obvious on a crowded train as there would be a big buffer space around you (just like most blacks get here anyways).