What forms are the verbs in "Omnibus rebus paratis, Caesar milites naves conscendere jussit"?

Question

In "Omnibus rebus paratis, Caesar milites naves conscendere jussit", what forms are the verbs "paratis" and "jussit", and why?

This sentence was taken from Gramática latina de Napoleão Mendes, from the chapter talking about the Absolute Ablative and Ablative Gerund (not sure about the names in English). Independent of the case the phrase is related to, the verbs were expected to be in participle form, which doesn't seems to be the case, seeing as the participle form ends in "-ns, -ntis."

"Paratis", as far as I know, is the 2nd person plural present for the verb paro, -are, and "jussit" is the 3rd person singular past perfect of the verb jubeo, -es, jussi, jussum, -ere.

The translation for the sentence given in the book is:
Preparadas todas as coisas, César ordenou que os soldados subissem nos navios. (Pt)
Prepared everything, Caesar ordered the soldiers to board the ship. (Partially Google translated)

Answer 1

You were spot on with your parsing of iussit; it is, in fact, the third person singular perfect active indicative of iubeō, iubēre, iussī, iussum.

With regards to parātīs (the macrons should give a bit of a spoiler regarding what it is), you were not quite there. It is the perfect passive participle of parō, parāre, parāvī, parātum, and is being used in an ablative absolute expression.

The whole phrase should be translated as such:

Omnibus rēbus parātīs, Caesar mīlitēs navēs cōnscendere iussit.

With all things (having been) prepared, Caesar ordered the soldiers to board the ships.

As a bit of a side note, Caesar's commentaries (to the best of my knowledge) are almost exclusively written in the third person; unless something or someone is being quoted, potentially ambiguous forms that look like personal conjugations (1st, 2nd person), like paratis (without the macrons, of course), can usually be assumed to not be personal conjugations.