> Why are only Hindu temples under the control of various state governments?
That is because historically, a lot of the land (farm and non-farm) came under the Hindu temples when the temples were under the administration of kings. The British East India Company took over the administration which then transferred to the provinces (prior to independence) and then the states post-independence. Different states then passed laws. For eg: See https://hrce.tn.gov.in/hrcehome/hrce_about.php for Tamilnadu state's Hindu religious and charitable endowments department.
> Religious minorities can run their own schools where they can teach their children their way of life? Can Hindus do this qua Hindus?
Ofcourse they do. I studied in a school ran by a Hindu trust and we had students from all religions. There was morning devotional prayers (Hindu hymns), friday bhajans (singing religious hymns) etc., and everyone attended. Stop spreading this hate about us vs them.
> When religions conversions are used to shift demography, this has national security implications
Ah, the national security bogeyman! Why don't you try shifting the demography of the armed forces to address that? I think men and women in defence forces from all religious backgrounds would have something to say about that.