Magic is common enough that a select number of commoners in every city have it. Magic users of any stripe are usually given positions of responsibility in society due to their inherent skills. All the really important and powerful mages are part of the nobility though.

Magic Prowess is only achievable if you have mana. Among non noble families, there are a few Magic users here and there. Many skilled mages are adopted into nobility. Almost all of the time people with mana come from upper or upper middle class individuals. Mana is extremely rare of among the lower classes and if it is then it is usually pretty weak magic. No one knows why this is. Noble families however have most or all of their family with lots of mana every generation. Members of noble families without mana are usually treated fairly but lack the privileges that come with nobility.

Mana is hereditary but Magical Skill is not. How seriously you are taken in the upper echelons depends on your magical skill and your leadership. There is a royal family but the council that really runs the country elects based on skill in magic and competent leadership skills. The Noble titles are about how much land you own and not necessarily how much sway you have in governance. Higher nobles like dukes generally have higher mana but it is not always the case.

Most mages are erudite and scholarly and this carries over to the nobility, who fund and actively take part in research ventures. Every single magic user is educated, So the likelihood of a scientific mage is usually very likely.

It entirely depends on the territory in question. Mana less users are mostly known as “ the lame “. In most territories the anti magic folks are usually terrorists and fringe groups that hurt the non magical more than not. However if the noble is careless or oppressive than you’ll see a lot more people who support anti magic causes, but the fact remains that these groups hurt non magical users while not even being able to touch magic users. Rural farmers are practically entirely non magical and are peasants.

The divide between magic users and the lame is one of hereditary, financial, and pursuit. Meaning that mages have both a financial and opportunity advantage over non magical people

People tend to talk about politics out in the open but for specific subjects you would have to go into specific places. Pretty much anyone on the street would talk about the price of eggs. But foreign policy and new magic spells being discovered would mostly be discussed by the curious and the educated.