My legal first name is hyphenated (on SS card), but my tax return forms have my first name without the dash and combined together as one. Will this be a problem/how should I input my name?

It shouldn't be a problem as long as your entire legal name is listed and is the same as the Social Security Card. If for some reason the tax return is rejected you can correct it by adding a space between the two first names and then re-submit.If accepted, you would not need to do anything further you are all set.