Of course. He can't teach them how to be him because the reflexes and twitchiness can't be taught, but he was good at understanding his opponents and what would and wouldn't work against them plus he was disciplined. Plus he's well connected and high profile which is half the battle at this point. I think he'll be able to do good things for Tank and Haney if they stick with him.
No. Floyd would be an excellent advisor-trainer, who would only be needed in a limited capacity, but as a fulltime coach/trainer that a fighter could rely on he'd be terrible just like Roy Jones was. To be an excellent trainer you have to put your charge first and I don't see Floyd being able to do it considering he hasn't been able to do it as a promoter.
I have no idea how Floyd became so good because his dad is a **** trainer. I think Floyd Sr lucked out that his son was a prodigy and was able to perfect what he shoved down his throat. He tries to teach everyone the same little patterns, shoulder roll and if it doesn't work, I guess they are the problem, not him.