Other than homeworkers (which is vague), freelancers (which is, to my knowledge, US-specific, and non-exclusive to this), what other words do self-employed people working from home describe themselves, that are uniquely highlighting these features of their working condition?
The term homeworker is only vague in the context you wish to use it in because it means someone who works from home. That person may or may not be self-employed.
The term freelancer is inappropriate in your context because whilst normally they would be self-employed it refers to someone who is hired for work on an ad hoc basis and they may or may not work from home.
The only phrase that meets both your requirements of self-employed and someone who works from home is self-employed homeworker.
There is an acronym, SOHO that refers to small office/home office but is generally used to differentiate market segments rather than refer to individual people. You could within the right context use self-employed SOHO worker or workers.
While telecommuter is used in the UK, I have also seen the use of teleworker.
I describe myself as a "home-based worker" in this context. I am also, as it happens, a freelancer, but as others have pointed out, the two things are orthogonal: you can be an employed home-based worker or homeworker, and you can be a freelancer who attends a regular place of work (in some cases your own office, in other cases clients' premises).
And yes, "freelancer" is in regular use in the UK.