The stars by a bitizen in the lobby indicate what you currently have employed on the floor matching their dream job. The gold stars indicate a bitizen with a skill level 9 is in their dream job. The silver stars just indicate that there is a bitizen in their dream job with a skill level less than 9. These are here ro help you quickly see if your floor has dream job employees and differentiate between bitizens with a dream job and those with a skill level 9 too. The stars in the elevator shaft have the same meaning for the floor they are on.
When you have a bitizen in their dream job they can stock twice the original stock amount. This is indicated by a x2 next to their item on the floor focus screen.
A bitizen's skill ranking determines the discount when stocking their floor. This is a cumulative number for employees on that floor and is indicated as a % off below the floor name on the floor focus screen.
Gold Coin icons:
The gold coin icons showing next to an bitizen in the lobby or from the Bitizen menu reflects the cost of hiring that Bitizen. The more coins showing (the scale is out of 5) the more expensive that Bitizen will be to hire. The cost is determined by their cumulative skill value.