The Frey+ only has 3 sets of outputs(Ha! Lots of pre's only have 1 set), and one of them is XLR. So one of your devices has to have XLR inputs, or its no go as you thought.
You don't need to use the Freya+ for your headphone amp if you have a separate dac, but if you want to: You could use a "Y" RCA cable on one of your Freya single ended outputs, that would give you 3 RCA outputs.
You'd need the correct type, male end on the single side and double female on the double side. then just use regular RCA cables for each of your devices.
Alternatively you could get a balanced to RCA cable for the XLR outputs on the Freya, just again make sure you get the correct ends for what you need. This output may be hotter, or higher in db, so watch for that.