I doubt the situations are similar, as there aren't any artificial implants in Adam's arm that boost damage resistance.
From what I gather, the implants are concentrated around the head and spine, they're not anywhere else in the body.
I assume their superhuman abilities are the result of the chip hyperstimulating their muscles/neural tissues to provide whatever abilities they have been assigned.
I assume they've been genetically modified to have higher durability in their body tissues, but that doesn't protect them from everything, they can still break bones, be crushed by heavy weights etc.
Bree has a particular vulnerability that if she doesn't rest between bursts of superspeed, she'll end up having a heart attack or burst the heart muscles, neither of which would be good for her health.
And no, they aren't robots. Nor are they androids.
They have organic brains, which makes them just as human as anyone else.
Actually, Marcus was inferior to the Lab Rats in terms of longevity/functional lifespan.
It was specifically stated his circuits would burn out before he reached his 16th birthday, causing him to die.
It was not specifically stated when he was created, but I assume he was fabricated shortly before encountering the Lab Rats.
If this theory is true, his expected lifespan is no more then two years.