INTELLIGENCE
I'ld say that "intelligence" is about having an ability to reason and learn. This makes "intelligence" a property of something, and not a thing on its own. There is thus no such thing as "an intelligence", just like there is no such thing as "a blue" or "a bitter". Rather, it's a property of something. This thing can be a human brain, or a computer or alike.
That also seems pretty consistent with our observations. Things that have the property "intelligent", are always physical objects with some kind of physical mechanism that produces the intelligence, like neural networks.
DESIGN
This is a rather ambigous term. There are 2 kinds of "design" imo. Natural design and artificial design. Natural design would be some, or any, "orderly" thing that was produced by, or was the result of, the forces of nature. Like a snowflake, a crystal, sand ripples, spherical planets, a nervous system, etc.
Then there is "artificial design". This would be something created by a thing with a certain level of intelligence. Like a car, a house or a robot.
The way to differentiate both would be a combination of knowing what the forces of nature are capable of on the one hand and having knowledge about manufacturing processes on the other. This is, for example, how geologist are capable of differentiating natural landscapes from artificial ones.
CAUSE
A cause is anything that produces an effect. This is a temporal phenomena. First a cause happens, then afterwards the effect takes place. Therefor, for causality to apply, a time dimension must exist. This is why talking about the "cause" of the universe is a nonsensical concept, since that would require something to happen "before" time itself existed.