My experience with both mint and lavender is that they grow much better from cuttings than from seed.
If you take a cutting in (for example) April, that cutting will have seven or so months to grow and develop a root system. But if you plant a seed of a perennial in April, the root system will have much less time to develop. This is the underlying reason that most sources recommend cuttings.
If you don't know anyone with mint or lavender plants, purchasing starts works well, too.
The annuals--basil, parsley, and cilantro--should grow from seed but, as you discovered, cilantro doesn't like full heat/sun when it's living in a container.
Your first question was, Do herbs do better indoors or outdoors? => They need lots of light, so outdoors is the way to go. My own basil, mint, oregano, thyme, parsley, etc. are in containers. My lavender is in the ground (I'm fortunate in my climate zone). I don't grow cilantro, because DH hates it.
What kind of soil are the herbs in? And what size are their containers? Maybe we can work something out for you from that angle. And does your back deck face south or some other direction?
Sunset Zone 17, USDA Zone 9