So some thoughts for consideration..
1. The moment you put helium in your DIL, you don't want to feed that into your suit so you will need a different gas source.
2. If you're just using air DIL but want your drysuit/wing/BOV and DIL to be fed from the same gas source, you can use a manifold/3-way splitter. Input can be QC6, output can be whatever you want (two LPI's for wing/drysuit, and appropriate hoses for BOV/DIL).
I tend to drive my DIL and BOV from off-board sources and use my on-board bottle strictly for drysuit/wing inflation. When in that config, my on-board reg has two LPI's for inflation, and of course an OPV. The off-board source feeds into a manifold by QC6 which then feeds into a BOV and my DIL source.
Sometimes when I'm doing open-ocean stuff I'll drive my DIL from on-board, in which case I replace one of the LPI's with a QC6 and drive the manifold from that. In this config, if I'm diving a drysuit I'll need a drysuit bottle. In this config, unless I reconfig my BOV for off-board and separate it from the manifold, I acknowledge and accept the BOV is only good for 2 or 3 breaths, long enough to get me onto another reg and no more. There's a huge trade-off here, and actually I prefer to not use a BOV in this config (because usually on a dive like this I'm likely to be using a hypoxic DIL).