Learn Dutch: Wij zijn samen. - We are together.

Wij and we both mean "we". Wij is the emphasized form, while we is the neutral, unstressed form. You could use we here if you are casually stating a fact, but wij is perfect if you want to emphasize that we (specifically us) are together.

Is zijn the same word used for "they are" and "you all are"?

Yes! For all plural subjects (wij, jullie, and zij), Dutch verbs use the plural form. This plural form is exactly the same as the dictionary form (the infinitive) of the verb. So "we are" is wij zijn, "you all are" is jullie zijn, and "they are" is zij zijn.

Both wij and zijn have an 'ij' in them. Do they rhyme?

Yes, they do! The Dutch ij makes a unique sound that is somewhere between the 'ay' in "say" and the 'i' in "hi". Since both wij and zijn feature this exact same vowel combination, they rhyme perfectly.