Cockloft insulation

I am looking into insulating the cockloft (space btwn ceiling and roof) of my Boerum Hill brownstone. The roof was recently replaced so the envelope is sealed. There seems to be a very wide range of approaches to insulating this space and I was looking for some input from those who have recently done this. 1st approach: closed cell spray foam against the underside of the roof deck and roof rafters. This will provide the air and vapor barrier, and with enough thickness will prevent a cold surface for condensation to form. The cockloft essentially becomes a conditioned unventilated space with the rest of the house. I do have some environmental concerns as well as some structural concerns such as if the installation isn’t perfect (air space btwn foam and roof deck where water can accumulate) and if/when anything needs to be done to the roof. 2nd approach: dense pack cellulose against the roof deck/rafters using a ‘smart’ vapor barrier that will allow inward drying of any moisture that gets into the insulation which preventing outward movement of humid air from the house to the cold roof deck. This would be more environmentally friendly but would require a contractor trained in techniques more associated with passive house renovation (we are aiming for improved efficiency, not full passive house). I equate this extra training with extra cost. The cockloft here would also be a conditioned unventilated space. 3rd approach: loose fill cellulose on the ceiling (as it currently exists) with a smart vapor barrier between the sheetrock and the insulation and careful attention paid to sealing all penetrations through the ceiling. This would prevent indoor humid air from entering the cockloft. In theory the cockloft remains vented so humid air doesn’t accumulate and rot the roof deck or cause mold problems in the insulation. The 3rd approach seems to be technically the easiest (and likely cheapest) approach, but my concern here is adequate air movement in the cockloft. Currently there is so much air movement due to leakage that moisture in the cockloft is a non-issue. If we seal the leaks as we are intending to do, then my concern is that there will not be enough air movement to prevent a moisture problem. Currently there is only 1 ‘doghouse’ style skylight about mid-roof for ventilation. Would this approach require additional vents placed? Has anyone done this with/without placing additional vents? Where/how many additional vents should be placed? Thank you