Converting 2.5V and 1.1V from 5V Power Supply with 10ms delay between both!
Because I had some available, I have used an LT3510 in a similar situation. Consult the datasheeet and you will see that it covers your requirements. I'm sure plenty of other devices from other manufacturers will manage as well, just use any supplier's parametric search. There is no lack of buck converters with multiple outputs, and many that offer separate output enables, sequencing features and so on.

If your design includes a microcontroller, it might make more sense to use that for your power sequencing. This could enable you to derive the other rails using simple linear regulators. If your current requirements are low, this may be a cheaper and simpler option.  Using a switching supply for the main supply rails and local linear regulators for subcircuits is a typical practice.