certainly. i never do ab isolation, squats, heavy compound movements that involve your abs/obliques will train them plenty without isolation.
also i know plenty of people who have six packs and haven't ever set foot in a weight room. they are some skinny ass mofos though.
in other words, having a six pack is a function of ab visibility which is a function of low bodyfat. you can do crunches and leg raises until you puke and never have abs if you arent' below 10-11% bf.
Having a 'six pack' without dieting/training means your bf is low enough to show muscle definition.
I have a buddy who is decently muscular, he doesnt lift weights at all, and his bf is around 6%. He does alot of drumming, which can burn a good deal of fat, but other wise hes just a skinny dude. But, he has a nice mid section, and he does no training, and drinks beer everyday.
Is there benefit to doing isolation ab work even if you're above 10-11% body fat? In other words, will having a stronger abdominal region help with the major compound lifts?
I actually so a picture of me before I started training, so I guess I was around 13 year old, with bf around 5% if I had to take a guess. Had an 8 pack..LOL
No training whatsoever besides runing around and playing. It's all about bf IMO
Is there benefit to doing isolation ab work even if you're above 10-11% body fat? In other words, will having a stronger abdominal region help with the major compound lifts?
Yes the stronger your core is the better you will be at the big lifts. Just make sure that you are doing low reps and high weight to build strength. I train abs in the 6-8 rep range and usually 3 sets.