Lustful can be used as both an attributive and a predicative adjective.
Lewd is more likely only to be used as an attributive adjective, but I don't see any problems with using it as a preicative one either - however, its not used very commonly as a predicative adjective.
You sentence does make sence, but reads awkwardly with lewd. It would read better as "He is so lewd a person".
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