[Buggy]

Yes that is a red tailed black shark and the tail is really more red-orange then true red. Yes they do get quite aggressive both with there own kind and sometimes with other fish also. I had two and one killed the other. I had to give away the survivor because it was also trying to kill my livebearers.
No he/she will not get lonely...they don't LIKE other fish in there territory. Even if you had more they would just drive the others away or kill them.
The danios might be able to stay out of the way but if you have all of the fish in your sig I doubt they could ALL stay out of the way.
I truely don't recommed that fish for your community tank.