Another thing the Council should keep in mind is that a long term lease isn't a guarantee that the team will actually remain that long. The day it's signed, it just becomes a cost of moving the team. Twenty years at four hundred grand, for example, just means it'll cost you eight million to pay off the lease. Actually, probably less, because the negotiating parties are an ownership that wants to leave and a city that doesn't want to get stuck with a stadium it can't do anything with until the lease expires.
Then, building the stadium is the beginning of a long negotiation, not the end. The Los Angeles experience with the Raiders is instructive, or San Diego's with the Chargers. The team ownership always wants some new improvement that it believes will increase its revenue, and there's always the implied threat that it'll leave if it doesn't get its way. This isn't a one night stand, it's the beginning of a long, and troubled, marriage.
The ideal use for those redevelopment funds is to continue the high-tech park idea, build a quality, hi-tech oriented campus, and subsidize rental for employers who locate their businesses here. That's the sort of thing cities have done for major sales tax producers, such as auto dealers, for years. There's no reason it can't be done with commercial property too.