ok for starters, try connecting the helix to the powercab plus, from the l6 link out - to the l6 link in. so u can control the powercab from the helix itself.
u want to create a send return or fx loop block at the end of your chain in the helix. connect a cable from the send 1 (or whatever u chose) on the helix, then to the in on the beatbuddy. then out on the beatbuddy to the return 1 of the helix. if the beatbuddy has midi, then u can control everything from the helix. midi in to midi out and so forth