What are the charactoristics of evolution?

What are the features that would be common to all xeno-intellegent beings?

Are there physical constraints to form?

How likely are other worlds to have creatures resembling our animals?

Premise: if a attribute has evolved several times on our planet then finding these facets on
aliens should be likely. If however, a feature has appeared only once in our Natural History
then it becomes less likely, etc.

Locamotion:
Flying: wings?
Walking: legs: how many what types, where?
Swiming: Fins, moving from side to side through the water. Jet Propelled? Tentecles?
Floating?
Digging?

Senses: Eyes? What kind? How many?
Smell? Are there different types?
Hearing: any rules to go by?
Touch: Where and when?
Sonar: Where and when?
Magnetic?