You are fine regarding the stocking as the tank is large and the minnows dont have that great a bio load so wont interfere with the filter.
BUT.... with the size of the goldies it may be hard to introduce small fast fish that the goldies will try to eat. Saying that though, the little ones are fast and the fancies slow and after the initial chasing the goldies will realise they cant catch them and give up, though you may lose one or two at the beginning, so get 6 to cover bases. Have plenty of planting for the little ones to hide in case it gets a bit much for them.
The dojos will be fine.
Please quarantine new fish