Hello,
Very clean and organized setup there. 
But may I make a suggestion? If it were me, I would honestly seperate them. If it's a W.C. animal (garter), what if, say, down the road the snake develops serious health issues or on a more mild case, external paracites i.e. ticks or mites. Being that the skink and snake are housed together, if one animal gets ill, there a VERY GOOD chance you will end up with two vet bills and/or two animals you'll have to tend too yourself.
I'm personally not a big fan of housing animals together, especially different genus or an entirely different species all together for the main reasons I mention above. The only time I put animals together is for breeding purposes.
But I have to say, I do like the colour contrast in the first pic. It is pretty and interesting to see the contrast of them. 