Choosing a name is a very important thing, and many factors need to be considered, including phonology, implication, cultural background and so on. According to your requirements, you can consider the following naming methods:

1. Take Yang as your brother's name: You can choose some names with Yang, such as Sunshine, Yangming, etc. These names mean positive and sunny.

2. Take the moon as your sister's name: You can choose some names with the moon, such as Yue Ming, Moon Moon, Moon, etc. These names mean as soft and gentle as the moon.

3. Combine Yang and Yue: You can combine Yang and Yue to form a meaningful name. For example, the sun is shining and the moon is shining.

When choosing a name, we can also consider the harmony of phonology and avoid unpleasant or unlucky syllable combinations when choosing a name. In addition, you can also refer to some name books or online name websites to find more inspiration and choices. The most important thing is to choose a name that conforms to the family cultural background and personal preferences, and give the child a unique and meaningful name.