In this particular context, I would use "elaborate" over anything else.

"elaborate decorations", "elaborate ornaments", etc.

The essential meaning of 「工夫をこらした」 is "not simple or plain".

To me at leat, "ingenious" would be too big a word for this.

In this particular context, I would use "elaborate" over anything else.

"elaborate decorations", "elaborate ornaments", etc.

The essential meaning of 「工夫をこらした」 is "not simple or plain".

To me at least, "ingenious" would be too big a word for this.