Firstly, I'm not sure about the source of the numbers given in the Wikipedia article. In 2007, the British Museum in London hosted an exhibition of the Terracotta Warriors. They published a book to accompany the exhibition, edited by Jane Portal, titled The First Emperor: China's Terracotta Army. It states that:
To date, more than 1900 sculptures of foot soldiers have been
unearthed. The majority of the figures are still underground and
untouched. It is estimated that all three pits contain around 7000
sculptures of soldiers, 130 chariots withe 520 chariot horses, and 150
That gives a total of just under 8000 statues. The army was completed in about 11 years (construction of the mausoleum took longer), so they were producing, on average, about 700 sculptures a year.
As for your first question, I can't offer a figure for a modern art student, but the PBS documentary Secrets of The Dead: China's Terracotta Warriors shows the process carried out by teams of skilled replica makers in China. It took about a month to complete a single figure based on a normal modern working week. (I think this may be the documentary mentioned by @SJuan76. I'm pretty sure it's available on YouTube).
The master craftsmen who built the original figures signed their work. So far, 87 names have been identified. Each master craftsman would have had assistants working for them. The current best estimate is that about 1000 people in total worked on the project. With 87 teams, each led by a master craftsmen, working on the project, each team would have to produce an average of just over 8 warriors per year for 11 years (in reality, the actual number would have been higher due to wastage).
Recent research at UCL suggests that the craftsmen were organised in a sophisticated labour model known today as 'Toyotism', which would have greatly improved the efficiency of the production process.
When they started the project, they had to learn how to make a terracotta army from scratch. It had never been done before. The rate of production would have been much lower in the early years, and would have improved over time as they gained experience. The experiment with the modern replica makers shows that it was quite possible to produce at least 12 figures per team per year once they had developed the skills.
We have no records of how long the working day would have been for the craftsmen who built the Terracotta Army. However, with 87 teams working a typical 40 hour week (based on the modern experiment), and each team producing a new figure per month, they could make 1,044 statues per year - more than enough to complete the 8000 figures within the 11 years.