On that Flax Council website I found answers to my questions:
Which is better for me, whole or ground flax seed?
Ground flax seed provides more nutritional benefits than does whole seed. That’s because flax seeds are very hard, making them difficult to crack, even with careful chewing. Grinding flax seeds breaks them up, making them easier to digest when eaten. Then the body can profit from all that flax goodness. If whole flax seeds remain unbroken, they may pass undigested through the body, reducing the nutritional advantage of eating flax seed in the first place.
What is the difference between brown flax seed and golden or yellow flax seed? Is one better than the other?
No, one flax seed is not better for you than another. Brown flax seeds provide the same nutritional benefits as golden (or yellow) ones. Both brown and golden flax seeds have plenty of lignans and dietary fibre, and both contain more than 50 per cent alpha-
linolenic acid. This is an omega-3 fat which offers you health and heart fitness. While some people prefer yellow-coloured seed in their cooking, brown flax seeds add the same nutrition to your diet as do golden ones. This means you can choose your flax seed freely. Brown flax seed may be more commonly found than golden, as more brown than golden flax seed is grown commercially.
Note: There is another yellow seed that looks like flax, but is not flax. It is most likely solin seed, a crop developed from flax. Solin seeds do NOT provide the same nutritional benefit of flax seeds. Solin seeds contain less than one-tenth of the alpha-linolenic acid found in flax seeds. Thus, the important omega-3 advantage of flax is missing in solin.