Silicone won't stick to PVC, but it will stick to acrylic (see post #32).
Silicone won't bond acrylic to PVC, or Tefen/Nylon to PVC.
Solvent cement won't bond Tefen/Nylon to PVC or Nylon to Nylon (yes, tried that as well).
Solvent cement (primary ingredient MEK, not THF) will bond acrylic to PVC .
...to be continued...
Looks like you may have already found a solution, but as a secondary option, you can get clear PVC pipe, so you can bond to solid coloured PVC fittings as normal: