I assume your are saying that athletes will earn $160 million in the state of Wisconsin. That is possible, but is probably a stretch. Brewers and Bucks combined payroll is probably closer to $130 million. There are also issues about where the taxes are due, Wisconsin or where you earn the money, but let's ignore this for the sake of argument. But, using the $160 taxable figure, that leaves around $150 million taxed at 7.65%, assuming no deductions (which, of course you would have for e.g. federal income taxes paid), giving you a revenue stream of roughly $11 million or debt service on $200 million. However, probably $7 million of the stream comes from the Brewers, which would be taken off the regular income tax income of the State. This would cause a huge fight in Madison. I think the best you can hope for is around a $1.75 million revenue stream. Now, this will provide debt service on $30+ million. Not a huge amount of money, but maybe enough with the ownership contributions, naming rights, and a possible facility fee on each ticket.
As I said before, I don't think paying for the Arena is that big of an issue. Very little tax dollars will be needed. $200 million from ownership, $75 million debt service from naming rights (roughly the same as Ottawa and Sacramento) and let's say $75 million debt service from a facility fee ($4 per ticket). Its the side projects everyone wants tack onto this project that will be the biggest obstacle to the Arena. People want to tie this project to an expanded convention center, a new PAC, updates at the zoo, park maintenance, etc. etc. etc.
BTW, the buyback is at cost plus $50 million. Its a fixed price, already negotiated. The Clippers sale has no bearing on the buyback. So, ownership would have a $50 million capital gain if the team is sold back to the league. The leagues taxable event would be upon the sale of the franchise to a third party.