We are already in a position where a second shutdown is ENTIRELY in Trump's tiny hands.
[Setting aside the most likely scenario in which McConnell and GOP Repukes remain so obsequious to Trump that there is a second shutdown because of Senate inaction.... ]
There is nothing Congress can do now to prevent a 2nd shutdown, if Trump is determined to do it for whatever reason. It does not matter if the bills pass UNANIMOUSLY, it does not matter if a veto over-ride is clearly in play, THERE IS NO MECHANISM TO PREVENT IT. Trump can have a second shutdown just because he feels like it, regardless of what Congress does or says.
The deadline was never Feb 15th -- because Trump is a petulant, defiant, narcissistic man-baby.
The deadline was passing a bill 10 days, excluding Sundays, before Feb 15th. The reason for this is that the POTUS has ten days (excluding Sundays) to decide whether or not to veto something. After that time, if not vetoed it becomes law.
But if Congress sends Trump something he does not like, and if he is convinced that his veto will be over-ridden, then just out of spite he can sit on it for a week and a half and create a shutdown just for the hell of it (while his instinct will be to lash out to veto quickly and loudly, the worms around him might convince him to do otherwise to get some revenge). Does anyone really believe he wouldn't behave thusly? It seems to me the only restraint on him vetoing quickly is his impulsivity and temper.