Windsor has considered to accept you already. i don't understand why you keep saying
"but I choose to be still considered by Windsor". I think what you should say "I still want to consider Windsor" or i have not mind up mind mind whether I should go to Windsor."
In any case, as soon as you provisionally accepted Ottawa, your offer from Windsor is gone... I think OLSAS misunderstood your question like me.
Yeah, um...I can't entirely dismiss the possibility that some people aren't really practicing law at all, and are just creating an entry on linkedin or something. But otherwise, we're talking about people who do, in fact, start their own practice and work in that practice. For some it may be something that they only do for a while, between working in other firms and for other lawyers. But it isn't a trick or a way to fill a hole in their resume. It's just self-employment, with all that implies.
Maybe you want to clarify your question. Are you asking about how you would set up for yourself and work as a sole practitioner? Or are you asking about how you would pretend to work as a sole practitioner?
What do you mean by "still considered"
If you received offers from Windsor and Ottawa, then as soon as you provisionally accepted either one, the other offer will be dropped.
You can still wait for others schools that did not give you an offer before you provisionally accepted Ottawa.
Therefore, your offer from Windsor will be dropped in this case.