Conference pear is said to be self fertile.....so does not need a pollinator. All you can do if a fruit tree consistently fails to flower, despite adequate watering, best growing conditions that can be provided, whether in ground or pot, is to replace it. The orange stains are pear midge. No real harm to the tree. You can remove affected leaves and dispose of by burning, not compost heap. I have an apple tree on limiting rootstock which was slow to grow initially, now it produces little blossom and no fruit......so it will probably be taken out and replaced. Now is a good time to line up a new tree, especially if it is one with fruit on it!