"Does using a repel from bag increase the frame?"
"Also, how rare is it to get a low IV spread frame to allow me to hit the nature I want?"
This question doesn't really make sense. Getting a low IV frame with a good spread is not very rare. For a given seed, you can pretty much get any nature you want.
"Also... is there a way to breed for 31 IV eggs yet?"
Yes. People are writing tutorials. Please be patient and / or read through the Gen 5 RNG help thread, which contains the answers to a lot of your questions.
I like to be helpful, but I don't have so much time to answer these general kinds of questions. You're much more likely to get a response on that thread.
First, you should hit that seed and catch something immediately to check its IVs. Those IVs should match IV frame 1 for the seed. If you can do that, you know you are able to hit that seed. Then you can restart and do the real advancing.
You start on IV frame 1, so if the frame you want is 46, you need to advance 45 times total, not 46. Luckily, that means less walking. Take 5 pokemon and walk 128 x 9 times to advance to the correct frame.
As for the PID frame, all that walking is going to advance it a lot. Just do the IV advances and catch the pokemon to see what nature and ability it has, and try to find that in the PID frames. After walking 9 x 128 steps, you will likely be in some PID frame above 2000. You should bring a synchronizer to have a better chance at the nature you want.
I would recommend trying to find a spread on a lower IV frame for your first try, because it saves time (walking, making mistakes, wrong nature). But, if that's the one you want, it is possible.