tonearm cable vs regular IC + ground wire

Not a stupid question at all. You can use any standard RCA interconnect and a separate single wire for ground. The key is to select a well shielded set of RCA interconnects to help prevent any induced hum.

My TT's are setup this way. I use regular IC's with no ground wire. Never had any problems.

A separate ground wire is not always needed. Try it with or without and go with whichever results in less (or hopefully no) hum.

Wireworld Atlantis 5 with a separate ground wire. Had Nordost Heimdahl dedicated phono cable with internal ground wire, didn't like it.

"Had the Nordost Heimdall dedicated phono cable with internal ground wire, didn't like it"

Mt10425, what did you hear or not hear with the Heimdall? I'm curious, because I'm just the opposite with the Nordost. Was this V 2.0?
Cable preference certainly is YMMV thing, along with ones willingness to open their wallet!
I'm slowly(can only afford used or an exceptional deal) fitting my rig with a full Heimdall2 dressing.
Currently, just table/phono amp/amp and power cord. The last piece of the puzzle-speaker cable(most costly)unfortunately, has been delayed. Haven't seen any listings for the latest version.
My ancient Blue Heavens fortunately, seem to be performing in their best light for now.

Not the V2.0. The original. I thought it was thin sounding with exaggerated upper mids and occasional shrillness on certain notes. It might've been the match with the Grado Sonata, who knows? My wife would cringe at certain frequencies.