My guess is as good as anyones, but I think Blender is used in many more commercial pipelines than known, it has it’s strengths and weaknesses, and if you have someone willing to work into Blender or already knowing it anyone would plainly be stupid not to gear up with a powerful and free tool.
None unless you plan to distribute Blender in an altered version with a linked non GPL library or don’t want to disclose the source of the changes. Content created with Blender itself and independent of Blenders binaries there are no limitations.
Guesswork again, I freelance, not as daily as I’d like though, depending on the order situation 
One thing’s certain, Blender alone will not do the job in an economic manor unless you’re in a very specific line of work where Blender shines, and everyone saying only use free tools, Windows is commercial crap use Linux, are just denying reality. If you need to earn money and have a deadline you use what gets the job done in the most efficient way. Sure you can do all in Blender if you want to, but only if you got no bills to pay and plenty of time to work around issues.
I for one advocate to plan a project, look at the requirements and choose the best tools for it, be it the OS, the asset management, the tool to sculpt, bake or model, to animate and to render. There are so many choises and I don’t see any sense in limiting myself to one package because it was so expensive, or to another package because it’s so cool to use opensource and free stuff only.
I see no sense either in using something with bleeding edge technology and fancy features I do not need.
Over the years this served me well, I got various licenses for small tools, often only in the 30-50 USD span and they all got their eligibility, form a nice pipeline by now and sumed up still are cheap.
One thing is the “backing up” - there’s no professional community per se, only a community of enthusiasts, some with more talent and knowledge and others with less, or those with no talend and staggering knowledge or vice versa 
It’s a motley crew.
So if you ask for advice you’ll either get no forum replys, replys to work around the issue, or to hire a developer to solve the issue or do it yourself, or someone fixes your problem with the first reply after 2 minutes.
Same goes for outsourcing actual tasks, there will be plenty of people answering in a wide spectrum of expertise and talent, some for whoms talend I personally wouldn’t pay at all and others who are surely worth every buck they charge.