No, it is not. Rest is needed for muscle growth. Do on alternate days or one every three days instead.
it all depends on how long you've been working out if you recently started (under any conditions) then it is bad for you. it could cause muscle damage and if you're not finished growing; stunt your growth
Don't believe all the rubbish you read it's actually quite difficult to over train as long as you are getting enough food and rest.
Eat sleep train repeat! Simple as that.
It all depends on how intense the workout is. If after the workout you are about to die maybe a rest is need.
Its healthy, its good to be doing that much exercise each day, but is it helping you achieve your goals