You mean the staff and faculty? I doubt green cards are necessary for any of them. We are talking about Minnesota here. We have a large Asian and Pacific Islander population in St. Paul. We get new immigrants -legal immigrants all the time. I’m sure we have some illegals from South and Central America, but they are a small percentage here. Vento is a school where less than 5% of the students are white (and I bet some of them are immigrants).
They have decided to stop celebrating holidays that few of their students celebrate at home. Most Twin Cities suburban schools stopped celebrating them 25 years ago. I don’t think it is a big deal - in Minnesota. It might be elsewhere in the country. This is why I am for local control over schools. Minnesota schools have different issues than schools elsewhere and St. Paul has issues that are unique to St. Paul.
Looking over your responses, it seems your are close to the situation and have information not in the article. As to local control - great, as long as it is smart with some alignment to the general American culture. Allowing polyglot to continue and be enhanced at every juncture only contributes to the hastening of the day everything dissolves into chaos. Had your thinking been prevalent during the mass European immigration of the late 19th and early 20th Century, America would have long ago broken up into enclaves of various languages/cultures fighting to keep their culture and avoid integration to the larger American culture. We also would have not been able to fight WW2 due to large populations that had not become Americans but were still identifying with their former country.