A ←s→ B ←s→ C

Wouldnt an argument like this be valid?

Some uni students study philosophy. Some students who study philsophy have 4.0 gpas. Therefore, some uni students have 4.0 gpas.

can this be translated as "most new yorkers do not ride the train?"m

wouldnt "some students" imply at least two students since "students" is plural? as opposed to just implying at least one like the lesson says.

Does anyone know why the second sentence in #6 is considered a red herring? It looks like a conditional relationship between the center and the eligible grant, with the condition having to do with the center's adoption rate and website.

Why wouldn't the tiger argument also be valid?

Why would it be wrong to interpret 5 as comparing very cold days to non-cold days? What about the grammar of the sentence makes this interpretation wrong?