Horatius Sermones II,5

[Katarina]

persta atque obdura: seu rubra Canicula findet
infantis statuas, seu pingui tentus omaso
Furius hibernas cana nive conspuet Alpis.

So original verse of Furius was: Iupiter hibernas cana nive conspuit Alpis, meaning that the Jupiter spat winter-quarters of Alps with white snow.
Here we have Furius tentus. Is he tentus with pingui omaso and he is spitting hibernas Alpis with cana nive, or he is just tentus and he is spitting hibernas Alpis with pingui omaso? But then I don't know what to do with cana nive ...

 

[Laurentius]

Tentus is with pingui omaso, you can also tell by how the sentence is structured.

 

[Katarina]

plerumque recoctus
scriba ex quinqueviro corvum deludet hiantem
captatorque dabit risus Nasica Corano.'


recoctus scriba ex quinqueviro - so the man had been quinquevir was transformed (recostus) to a scribe
corvum deludet hiantem - alluding to the fable about the fox and the raven, the fox talking to the raven how good he sings and the raven showing that looses the slice of cheese that he has it in it's mouth. So if I am correct till now he is saying that it often happens that a scribe is praising someone (the one writing down his will?) that he get some of the heritage?
captatorque dabit risus Nasica Corano - legacy-hunter Nasica will give laughter to Coranus - so Coranus is going to laugh because of Nasica. So here it is said that the Coranus is going to uncover Nasica's plan for legacy hunting? I don't get that part ...

 

[Katarina]

'tempore quo iuvenis Parthis horrendus,

Is that Dative or Ablative?
Dative - he was terrible to the Partes / for the Partes
Ablative - he was dreaded by Partes
I think for the Ablative officially there should be a Parthis but I've read that Horatuis leaves the prepositions out when using Ablative many times ...

 

[Pacifica]

plerumque recoctus
scriba ex quinqueviro corvum deludet hiantem
captatorque dabit risus Nasica Corano.'


recoctus scriba ex quinqueviro - so the man had been quinquevir was transformed (recostus) to a scribe
corvum deludet hiantem - alluding to the fable about the fox and the raven, the fox talking to the raven how good he sings and the raven showing that looses the slice of cheese that he has it in it's mouth. So if I am correct till now he is saying that it often happens that a scribe is praising someone (the one writing down his will?) that he get some of the heritage?
captatorque dabit risus Nasica Corano - legacy-hunter Nasica will give laughter to Coranus - so Coranus is going to laugh because of Nasica. So here it is said that the Coranus is going to uncover Nasica's plan for legacy hunting? I don't get that part ...

I'm sorry, I'm not sure about this—the references are obscure to me—but at least you seem to have got the grammar right.

'tempore quo iuvenis Parthis horrendus,

Is that Dative or Ablative?
Dative - he was terrible to the Partes / for the Partes
Ablative - he was dreaded by Partes
I think for the Ablative officially there should be a Parthis but I've read that Horatuis leaves the prepositions out when using Ablative many times ...

It is dative. It would be weird to have an ablative of agent with horrendus, and ab/a isn't omitted before an animate agent, even in poetry.

 

[Pacifica]

the references are obscure to me

Lol, the next line says:

'num furis? an prudens ludis me obscura canendo?'