3. What calculations should Julis make  to get a grasp on quickfix's
financial performance?

Looks like you are doing a case study that involves analyzing a firm's
accounts. There are a number of common, recognised financial
calculations designed to be performed on financial accounts (balance
sheets, income and cash flow statements, etc).

You can find a list of these financial ratios - including an
explanation of what they are measuring and examples demonstrating how
to calculate them - at the following sites:

http://www.investopedia.com/university/ratios/ratios1.asp

http://www.bized.ac.uk/compfact/ratios/

http://www.accountz.com/ratios.html

While all the categories of measures (asset/inventory management,
financial/investment measures, liquidity, leverage and profitability)
fall under "financial performance", the ones you probably need to
focus on for your case study are the ratios listed under "performance"
in the first web site I gave.