Re: Altium's Dashboard
Slotted pads are routed, not drilled. Whether or not it adds cost is up to your fab. The one I use (Gorilla Circuits) doesn't charge extra.
If there are no blind or buried vias, the plated hole drilling is done as the next step after lamination of the board. The holes are drilled and slots to be plated are routed, cleaned, coated with carbon, plated, and cleaned again. The board is then drilled and/or routed again for the non-plated holes and slots, and the holes are cleaned. If you have any gold, silver, or tin plating it is done next. Then the soldermask is applied, and finally the silkscreen is applied.
Masks are optically aligned with the finished board, as are the silkscreens.