These sources don’t seem reliable to me. For example, a passive voice for provenir makes no sense whatsoever. Maybe these website automatically generate a passive / pronominal voice, maybe it’s a mistake, but these simply don’t work.

1/ Checking a 6 000-word list is a bit arduous and error-prone. We could correct it, give you other lists, but there is no recipe to know if a verb has a pronominal form or not, except checking a good dictionary / thesaurus / Bescherelle. So at some point, you need to decide which of your sources are more reliable than others, and trust them. For example, I wouldn’t trust a german website which looks automatically generated over a human-generated french Wikipedia page. The Wikipedia list may miss some words, but at least it shouldn’t be overzealous and list verbs as pronominal when they shouldn’t.

2/ The passive voice works by inverting subject and object : “object is verbed by subject” instead of “subject verbs object”. If a verb can’t have an object, it can’t have a passive voice. You need to check if a verb is transitive or not. There are three cases :

• Directly transitive : verbs that need a direct object (complément d’objet direct / COD). These are the majority, and can use a passive voice.

• Indirectly transitive: these verbs need an indirect object (complément d’objet indirect / COI), introduced by a preposition (like provenir : Le français provient du latin). They have no passive voice. This category is often agregated with the next, intransitive verbs, as it doesn’t change much.

• Intransitive : no object, no passive voice, like falloir. Actually many theoretically intransitive verbs are used with an object in some cases (il pleut des cordes, il faut du courage pour…), but they still don’t have a passive voice.
  I found a list of intransitive verbs here.

3/ Some verbs are exclusively pronominal. Your Wikipedia list has a subsection for them, actually. There is no verb that is exclusively passive, though.

I don’t know exactly how your script works, but to populate it you should try to find a source that gives you these kinds of attributes in addition to just listing words : groups, transitivity, pronominal form, etc can’t be guessed easily, but a good dictionary provides them.

It’s not in your question, but you will encounter this problem : the pronominal voice is often used instead of the passive. “Ça s’explique facilement” means “it’s easily explained” instead of “it explains itself easily”. And in many cases it is the only option one would use, or using the “normal” passive form doesn’t mean the same thing. For example : “Ce problème s’explique par cette cause“, the “pronominal passive” voice, means that the cause is the explanation for the problem ; whereas “Ce problème est expliqué par cette cause” would mean that the cause gives the explanation. Context can help the reader understand, obviously, but usage implies that these two forms have different meanings. And we tend to use this form even with verbs that shouldn’t have a pronominal form : “Ce cheval se monte facilement“, “this horse is easy to mount”, is the only case where one would use se monter.

EDIT : following Law29’s comment, I realised there is one more case where we use the pronominal voice : instead of [verb]ing one’s [object], one [verbs] oneself the [object] : se cogner la tête instead of cogner sa tête. It’s still a different case of the usual pronominal voice, as meaningwise it’s more of an active voice in disguise.