May I ask in which dictionary you found "benigne" and what exactly it said there? I as a native speaker can tell you that 99% of all native speakers of German woudln't have any idea what "benigne" is supposed to mean (except for its medicinical and its Latin meaning perhaps).
Why did you now change it to "harmlos"? ("harmless", "innocuous")
I don't think that's what it means nor does it fit.

And yes, "creditur" is 3rd person passive of "credere" ("to believe" or "to trust"), so it means "he/she/it is being believed".
But in German there's no difference between "man glaubt, dass" und "es wird geglaubt, dass", the former way being the normal way to express that. And "glauben, dass x ... ist" und "x für ... halten" also means roughly the same.

And only "Gott" sounds fine to me, "lieber Gott" is an expression normally only used by children, ironically or in collocations (well, at least that's my experience).

"gutartig" also is a medical term and only used to refer to tumours etc. (the same as "benigne"). You could have noticed that looking at the words below that on dict.cc.
And you also shouldn't use an English to German dictionary when translating from Latin to German since the English words often have a meaning different from the one they had in Latin. A fairly good Latin to German dictionary is this one: http://frag-caesar.de/
But there are many words missing in it - I rather use it as a help to figure out which case or tense a word has.
Well, according to Duden, "gutartig" can also refer to a person but for me that sounds really old fashioned, I wouldn't use it that way at all (not even when trying to sound archaic).

Scieras Anmerkungen kann ich mich anschließen, abgesehen davon würde ich "testen" nicht verwenden, das ist mir zu technisch, bzw. ein Anglizismus, Gott PRÜFT den Menschen (z.B. Hiob); Kyrie ist griechisch für "Herr"; harmlos ist hier falsch (ergibt keinen Sinn)!