How much do I earn from each paid-task?

As I mentioned, the amount you are paid depends on the previsouly stated factors. As an Unbabel translator myself I can assure you an average of 0.05$ to 0.60$ per task. They do pay well, I have even been paid a 1$ for some micro-tasks that required me to re-written all the machine translation. As you get better and better, producing good quality translations, your hourly pay increases, consequently your earnings do to. The standard hourly pay is 8$, in my case as an example I'm already earning 12.77$ per hour, but if my rating drops (currently 4.7/5) my hourly rate will too.

How do we cash out the money? What is the minimum amount and do they pay?

After a minimum of 5$ is met you can cash out your earnings. Yes, Unbabel is not of those companies who require you to have a 100$ balance in order to chash out the money. The payment is done to your Paypal account in 4 days. They do not do monthly payments, we decide when to cash out and the payment is done as quickly as possible.

They pay. I have been a Unbabel Editor (Translator) for the last 3 months and I have earned 350$. It's a good extra income and it can become an extra salary at the end of the month if you have a wide set of languages and you are willing to put in some work.

Are there always mini-tasks (translations) to do?

No. But this depends on the languages you are able to translate. For example I know Portuguese (Native), English(First) and Spanish. And I can not translate from English to Spanish. So I can only do tasks when there is work fitted to my capabilities. Do not expect it to become your full-time job, more as a regular hobby which earns you a few good dollars.

Translate on your phone/tablet wherever you are.

Perhaps this is one of the biggest winning factors for Unbabel, they have an app. And yes you can be doing your micro-tasks wherever you go. I used to be sitting on my translation classes learning and doing tasks on Unbabel. Is there something better than learning and earning at the same time?

How do I become a Unbabel Paid Editor?

Editors is what Unbabel names their translators. So you wanna join the company and put your skills to work, great! Sign up and complete the learnings tasks. It only takes about 5 to 10 micro-tasks on each language you want to translate in. After, other Paid Editors will review your learning tasks and give you a rating. If you are good, you become a Paid Editor. Don't worry. it will not take forever for you to be accepted, for me it only took 1 week until I was doing Paid Tasks and cashing in.