Yep - it all stacks (including with the regeneration skill, which can give you another 0.7% if you max it out).
But it's important to note that regeneration is also a percentage of your total health, so increasing your total health also increases your effective regeneration rate as a side-effect.
At level 40 my Mage had 800 life points, and I then enchanted all four armour pieces with level 10 lifeline (+400 health, to give me 1,200 total). So as well as the extra health, I'd increased my regeneration rate by 50%. I think it was a far more effective use of those Malachite gems than just adding 4 level 10 health regens, which whould have been a total of 1.2% increase in health regeneration.