I lived at the bottom end of Temple Crescent at No 8 between 1971 -76 as a child and our back garden was overlooked by a huge old house which must be the Old Orphanage you describe although I had no idea at the time what it was then or had been but it always seemed very dark and eerie, almost deserted ( I never remember seeing any signs of life ) so thanks for posting all this information it's amazing what you can still learn 50 years on. There was a big stone wall running along the back of our garden and the big house was tight to the wall as I recall
The Daviot playing field was a magnet for youngsters of my era as well and continued to develop youngsters who went on to play Highland League for local teams ( Charlie Christie and John MacGillivray were certainly regulars there in my time ) Come the summer holidays it was run out the door asap after breakfast to join a game there and play as long as light held, perhaps venturing home for some refreshment. Although not a regular at the field Willie Sutherland used to come up from Fort William to visit his grandparents in the holidays. they were our neighbours in TC and we played head tennis between the back gardens with washing line poles used as goals.