A number of those things are in fact not specifically spelled out in scripture ...
True, but they are implied.
The idea that Scripture must necessarily 'spell out' its totality of meaning is itself trefuted by Scripture – nor is it an understanding within the Abrahamic Traditions.
Not even the Reformed churches declared that the total meaning of Scripture should and is self-evident to everyone – and clearly it's not. The idea that because I can read something I understand it fully is somewhat naive.
In the New Testament, there is no mention of the papacy,
Actually there is. To what extent the Office of Peter has authority over all, or is regarded as 'first among equals' as the Orthodox have it, is a matter for discussion. But it's clear from various gospel texts and moreso from Acts that Peter was considered the leader of the Twelve.
worship/adoration of Mary (or the immaculate conception of Mary, the perpetual virginity of Mary, the assumption of Mary, or Mary as co-redemptrix and mediatrix)...
We don't worship Mary although I will allow in the popular mindset it hard to see the difference – I rather see it as telling that the Divine Feminine simply will not go away ...
But the Marian Dogmas are upheld by the wider Church, informed by its own faith, by sound reason, strong theological argument.
The Immaculate Conception (that Mary was not subject to Original Sin) has neither a direct transmission in Scripture or Tradition, but popular devotion grew over the centuries and when the dogma was put to a free vote by the bishops, more than 90% agreed.
Theologians argue that Mary, as 'the New Eve' (which is an acient tradition) would enjoy the same sinless state as Eve prior to the Fall. Theologians reference
Genesis 3:15: "I (God) will put enmity between you (the serpent) and the woman (Eve),". This is seen fulfilled in the Book or Revelation – the Woman crowned with stars and trampling the Dragon underfoot.
The Angelic Salutation in Like 1:28 – "Hail, full of grace, the Lord is with thee..." and again in 1:30 – "Fear not, Mary, for thou hast found grace with God." both would imply a 'state of grace' – when I did my degree, a question was asked: Was Mary baptised, and by whom? To which the answer is Yes, by the Holy Spirit prior to her conception, but precisely when is unknown, although a strong tradition suggests from her own conception – that is she was baptised from the get-go ...
... petitioning saints in heaven for their prayers ...
Already, if recent, a Jewish tradition ... basically if the dead live on in some form, why would they not seek the best for us?
Again, a question was put: Would Christ found a Church, and make no provision for its continuance?
I believe many of these however are within all Orthodox churches. Perhaps they grew from some Jewish folk traditions -- I don't know if that is known (obviously the Marian adoration wouldn't be, but ideas not unlike Purgatory and ideas of the authority of rabbinic tradition and scripture would be)
Pretty fair assessment.
As ever, people criticise 'the Catholic Church' when they think of the RCC, ignorant or ignoring the fact that the dogmas and doctrines they see as 'invented' were there long before the RCC emerged as a specific entity – and often the supporting arguments for them are stronger in the Greek Traditions than in the Latin.
