This may well be adjusted slightly by the Court in the coming days. But based on the Court's rules, absent further modification, here are the tentative due dates for the briefs. (Note that all of the parties are a petitioner and a respondent in at least one of the cases. Thus, the United States, the NFIB, and the states will all be filing briefs as petitioners and briefs as respondents.)
1. December 29: briefs for the petitioners.
2. January 5: amicus curiae briefs supporting the petitioners.
3. January 30: briefs for the respondents.
4. February 6: amicus curiae briefs supporting the respondents.
5. March 7: reply briefs for the petitioners.
With this briefing schedule, it seems likely the Court would hear the cases the week of March 26. Currently, March 26, 27, and 28 of that week are scheduled as argument days. The justices can adjust things as they please, but it seems most likely that the Court will schedule these arguments for one or two of those days.