Since you've already made the maximum permissible IRA contribution you can ignore my suggestion to make such a contribution. With a $10,000 self-employed health insurance deduction you have sufficient compensation to support the IRA contribution since $8,000 of that $10,000 is doing double duty. The IRA contribution therefore has no effect on the amount that you can contribute to the 401(k) while still keeping the $10,000 self-employed health insurance deduction.
Fidelity's self-employed 401(k) plan does not include a designated Roth account so no Roth contribution can be made to that plan.
There can't also be a SIMPLE IRA plan and there is no point to a SEP plan since the maximum permitted employer contribution to the SEP plan would be the same as the maximum permitted employer contribution to the 401(k) plan.
