I am aware Shadowrun 4e says none of the Technomancer's Persona's attributes may exceed their Resonance attribute, but what of its "Other Ratings"? Are Biofeedback Filter and Matrix Initiative limited by Resonance too? Because my Technomancer's Matrix Initiative was calculated as 11, which is considerably more than my 5 Resonance. Do I get to keep that higher number or not?
You get the higher number, but not always that high.
The Matrix Initiative is listed under "Other Ratings" in this table, and, therefore, is not limited by Resonance. However, remember that your Matrix Initiative is Intuition + Response + 1 (hotsim), where Response is limited by your Resonance.
The Resonance measures how well your character is attuned to the Matrix, and it limits not only the personna attributes (firewall, response, system and signal) but also the complex forms you use.
So your Matrix Initiative is indeed Intuition + Response (which is the minimum value between Intuition and Resonance) + 1 (because technomancers always operate is hotsim), and this value will exceed the Resonance of almost anyone. Don't forget that, unlike hackers, technomancers may run as many complex forms as they like without affecting their Response.
And for the Biofeedback Filter Complex Form you receive automatically from being a Technomancer (at a rating equal to your Charisma), it is, as any other Complex Form, limited by your Resonance. So your Biofeedback Filter Complex Form rating is equal to the minimum value between Resonance and Charisma.