This website may help clarify. https://www.spanishdict.com/guide/demonstrative-adjectives-in-spanish
When do you use 'aquel' rather than 'aquello' to describe masculine 'over there'?
Aquellos is plural. Aquel is singular. I don't believe there is an "aquello."
aquel vestido... "that" is directed to the corresponding gender of dress (m). so 'aquel vestido' compared to 'aquella camisa'.
Fernanda is a female name, NOT A male name. Reported. >:(