yes they will be. though they may be small as they will be overcrowded. give them plenty of water.

Yes. This is how they grow in the wild. Not in bags of course. You might find because there are more potatoes in the bags than is recommended (because you did not harvest them last year) they might be more susceptible to disease like blight. You also need to ensure they get enough water to grow to a size suitable for eating. Can you remember which potato variety you have and whether they are early or later varieties. It will be interesting to see what you do harvest from the bags. If they are late potatoes you could give them a liquid feed of tomato food type fertiliser as long as the soil is well watered first. Keep us posted as lots of members are interested in growing in bags.