Nintendo Switch Joy-Con (L) Gray
No, the straps are sold separately.
Yes , drifting is a highly common isssue with all Nintendo switch joy-con but nintendo has a policy in place to repair if your request through their customer service for a fix free of charge.
Yes and yes.
They joy cons do not need tobe attacked to the switch to use, they can be used with either a controller to keep them together or separately - similar to the wii remotes.
Yeah, drifting issues seem to be pretty common. Typically it's just dust that's found it's way into the sensor of the joycon analog sticks, and Nintendo suggests taking a clean soft bristle toothbrush and gently cleaning the dust from them, or even a QTip, and that should help the issue. Also try updating and recalibrating your joycon. Otherwise if the issue persists you may have to get in touch with Nintendo.
Yes they are!