1) While dragging the layer, mouse-over to the left until the blue horizontal marker changes position and touches the left side of the Layers panel. This will place the layer as a sibling of the other layers rather than a child of one of them.
2) I'm not sure if i understood you correctly but there's a couple ways to go about this:
To fill the image/symbol (assuming it's a transparent PNG) press and hold ⌘ (cmd) and click on its thumbnail in the Layers panel to create a selection around the symbol then go to menu Edit ▸ Fill... select Custom colour and pick the colour you want, then click Apply.
To create the stroke:
the simplest way is to select the image/symbol layer, click on the FX icon on the bottom of the Layers panel, put a tick on Outline and make sure its selected to change its properties, give it a radius. make sure the Alignment is set to Outside and pick a colour.
alternatively, press and hold ⌘ (cmd) and click on its thumbnail in the layers panel to create a selection around the symbol. Go to menu Select ▸ Outline... give it a radius and set the alignment to Outside. Now to fill it with a colour go to Edit ▸ Fill... select Custom colour and pick the colour you want, then click Apply.
vzfy reacted to MEB in I have a few questions about things in Affinity Photo.