1.) Yes, but if you know CSS it is easy to learn. So if you think that is something holding you back I would recommend deviating from the absolute truth when asked. Everyone “deviates” slightly from the truth on resumes and interviews anyway – its called marketing and it is expected.
2.) Yes, chrome and firefox box have mobile views.
3.) Yes, again if you know CSS the technical execution of responsive design isn’t difficult to grasp.
4.) Perhaps but I think a majority of “freelancers” are inexperienced bottom feeders hardly making any money. The notion these days seems to be freelancing is the alternative to not being able to get a real job. Which is completely the wrong mentality but that is the way it is considering the abundance of cheap jobs out there. I see posts day in and day out on this very forum that prove this very reality. Basic questions which someone offering professional services should know and if they don’t certainly are not qualified to be running their own business. People don’t think of freelancing as a business anymore which is the problem.