eh, maybe alittle. I have a 2213 on a 10g, about to upgrade to a 20g and am keeping the 2213. I am not sure how much greater the flow is on the 2215, but worse that could happen is its too much flow and you are forced to face the spray bar at the glass.
In my experience the diy reactor will not decrease flow much. I think the 2213 would best suit your needs. You may have to drill spray bar holes a little bigger to back off flow. I'm not sure if you have seen one in person but a 2213 is quite large. I had one run a 30 gal planted tank with an in-line reactor and no problems.
Have you considered a xp1. I have no experience with rena filstars but I think it would be an option.