Hi- I have a couple questions about sanding. Please help 
1. I want to stain the kitchen island,but not sure I need sand more or not. Please see the pictures. When the wood is wet,it looks like uneven colored with some finishes left. However looks fine when dried. I'm afraid the whole pierce would look horrible after staining.
2. There are some veneer strips on the bottom and side of cabinets and toe kick. Should I sand or just degloss them using actone or tsp?
3. I heard that it is about the same cost to mask the cabinets or spray the inside. Any sanding needs to be done for inside of cabinet before spraying?
It is so confusing to me and thank you for your help!

1. I want to stain the kitchen island,but not sure I need sand more or not. Please see the pictures. When the wood is wet,it looks like uneven colored with some finishes left. However looks fine when dried. I'm afraid the whole pierce would look horrible after staining.
2. There are some veneer strips on the bottom and side of cabinets and toe kick. Should I sand or just degloss them using actone or tsp?
3. I heard that it is about the same cost to mask the cabinets or spray the inside. Any sanding needs to be done for inside of cabinet before spraying?
It is so confusing to me and thank you for your help!