I have noticed little hairs with a tiny green ball at the end on the bottom side of the leaves on some of my million bells. What are these and should I be worried about them?
Great find!
Those precious eggs hold what will be Green Lacewing babies. They are hung on threads to keep them from predators. The threads are made of mucus that has hardened in the air.
Green Lacewing will eat lots of Aphids in your garden, they also will eat good butterfly eggs, so you need to determine if they stay or your evicting them!
what do I do its a beautiful basket and its turning brown the new buds
If this is webbing that you are talking about, then it is likely spidermites. Usually, once it is covered in web, it is to late, and the plant will not recover.
Should you still want to make an attempt at resolving this, then this article will help you: https://www.gardeningknowhow.com/plant-problems/pests/insects/spider-mite-treatment.htm
Do million bells need constant deadheading or are they self cleaners ?
You can dead head at the same time you pinch them back.
https://www.gardeningknowhow.com/ornamental/flowers/million-bells/calibrachoa-million-bells.htm
How close should Million Bells be planted? Thank you.
Not necessarily, but planting them close together makes it easier for them to spread if the plants do get aphids. Plus, lack of air circulation can promote fungal diseases.
Many baskets purchased with million bells are planted closely because they contain several colors. If you are planting in a garden, you can plant them further apart. In a 12 inch basket or container, I suggest planting no more than three small transplants.
https://www.gardeningknowhow.com/ornamental/flowers/million-bells/calibrachoa-million-bells.htm