WordNet is a great finding but it's hard to say how useful it is for Panlexia. WordNet is a monolingual English database and it doesn't link to any translations, as you said. However, I found a word list in Concepticon,
Borin 2015 1532, which "contains an additional mapping to the Princeton Wordnet".
I tried a few searches on the slow web interface and found out that WordNet provides good semantic categorization. For example
dream has the categories <noun.cognition> in the sense of 'a series of mental images while asleep' and <noun.feeling> in the sense of 'a cherished desire' among others. So WordNet truly grasps the polysemy of English words. As a verb, WordNet categorizes
dream as <verb.perception> and
sleep as <verb.body> whereas in Concepticon both were in the Body category, which is clearly wrong.
So it seems like WordNet categorizes concepts better than Concepticon. Therefore we can consult WordNet when we try to figure out, which category a word should go. By the way, WordNet categorizes
brass into <noun.substance>.

WordNet is a great finding but it's hard to say how useful it is for Panlexia. WordNet is a monolingual English database and it doesn't link to any translations, as you said. However, I found a word list in Concepticon, [url=https://concepticon.clld.org/contributions/Borin-2015-1532]Borin 2015 1532[/url], which "contains an additional mapping to the Princeton Wordnet".
I tried a few searches on the slow web interface and found out that WordNet provides good semantic categorization. For example [i]dream[/i] has the categories <noun.cognition> in the sense of 'a series of mental images while asleep' and <noun.feeling> in the sense of 'a cherished desire' among others. So WordNet truly grasps the polysemy of English words. As a verb, WordNet categorizes [i]dream[/i] as <verb.perception> and [i]sleep[/i] as <verb.body> whereas in Concepticon both were in the Body category, which is clearly wrong.
So it seems like WordNet categorizes concepts better than Concepticon. Therefore we can consult WordNet when we try to figure out, which category a word should go. By the way, WordNet categorizes [i]brass[/i] into <noun.substance>. ;)