Monday is the day where release 1 ended.
I doubt that there will be an event later that evening but it could be that Vivian gets texted by Christian asking about the progress for the little project.
I think purple happens after scouting out a location as she gets picked up by a driver.
Only possible if Christian sends a text to Vivian. He apologizes to her for not being able to attend the clients meeting and tells her she should take over the meeting as she knows the location. He also mentions not to worry about drinking something as he sends a driver to pick her up.
It could be that the meeting with the client happens on a friday as likely as the basketball game takes place at that day.
The purple dress event - meeting with Mayor (can't be at an official location as he is married and fears rumors or his wife) - somehow Vivian being in Mayor's house - fleeing from there late in the night - ending up somehow at Marcel's house who before was celebrating with his friends deep into the night because of their win and crossed Vivian's path - Vivian showering there - Vivian fresh showered gets a ride to her home.
So scouting out a location (black dress, curly hair cut) happens early in the week. Tuesday or Wednesday.
Friday is the basketball game and the clients meeting.
Saturday Barbeque (Garden Party) at Christian's house and maybe during the day the twins organized sth for Vivian (bikini event).
As Vivian is a part-time teacher and the regurlar one Mr. Pryzbylewski has taken over again on Monday she has now a lot of free time and I hope for Huutch that the car is still running as it should

.
Is Christian offering Vivian an office spot at his company?!