Option 1 allows the user to see more list items at a time, so it is preferred when the user is likely to need to jump around a lot in the list (e.g., to find the next record to edit). More items means less scrolling, among other things.
Option 2 can usually get the user to editing the field faster, since there is no waiting for a new browser window to open and no cognitive re-orientation needed by the user, so it is better for heavy data entry (e.g., making a change to every record, one after another).
Both options are substantially inferior to edit-in-place in the table by using an editable grid or replacing your table with an array of appropriate controls (text boxes, combo boxes, checkboxes, etc.) that are populated with the field values for the appropriate set of records. Users change fields directly in the table and select a Save button or menu item to update all changed records at once. Or you can save automatically whenever a field loses focus, if your bandwidth can handle it.
Compared to Options 1 and 2, edit-in-place has the following advantages:
No need to click an Edit button to change a record, an additional navigation step that takes time and learning (e.g., the user has to learn the “edit” icon).
No need to visually re-acquire the fields in another location in order to edit them, making editing faster and easier.
No second window or form layout to learn and understand, and to consume screen real estate that the user may want to use for something else.
No modes –the users can fluidly switch between editing and viewing, and save whenever its convenient.
If you have too many fields for the Employees to show in the table even with horizontal scrolling, then you need to choose between (1) having a split-screen master-detail layout in a single window, and (2) having two windows and allowing drill-down. However, optimizing the display of “extra” fields is a separate issue from how to edit records. The general rule for usability is that if a field can be edited by the user, always make it editable for the user wherever that field appears, whether it be in a table, a detail overflow area of the screen, or a separate drill-down detail window.