It sounds like you already have the problem and solution in your mind before you land. Even if you end up being right it might be good to approach the problem w

It sounds like you already have the problem and solution in your mind before you land. Even if you end up being right it might be good to approach the problem with a black slate and do discovery as if you know nothing rather than with an agenda. The other factor to be aware of is when people's income and livelihood is at stake they will fight tooth and nail about everything. If you give the team ownership in creating the solution and make it about co-creating the product you might have better long term success. However, if the deadline doesn't permit that, then the short term solution is to map out a process like you described and find out who's on board and who's not. Remove those who offer resistance from the team because an anti-team player is death for a deadline.