Just for everyones information, Pikachu has a 0 to 60 fthrow CG on falco, and a 20 to 100 Dthrow CG which can be led into with two fthrows from 0%. A good rule of thumb for how long itll last is by adding and subtracting 10%. If you get grabbed at 30 itll do about 90, 40 to about 80, etc. Its not exactly right but its close. Also, that last percent includes a regrab, so at 100% you are in pikas hands, and I believe he can do one last dthrow and then a usmash on falco which adds about another 20%. Its not a 0 death, but following the usmash it could lead to a well placed QAC to thunder which I would recommend avoiding rather then trying to shine. Another thing about the CGs is that if you are killed soon after the CG the diminshed dthrow wont be able to chaingrab unless its refreshed, so smart pikas will probably try to refresh it before you hit 20%. As far as getting grabbed, pika has a few moves which can lead into them. Fair is popular though easy to avoid, utilt and uair can lead to grabs, so can dtilt and dair if the opponent isnt wary. Of course pikas will use their speed to go in for one, he's more or less as fast as MK to give you an idea so he can punish attack lag with a grab pretty easily.
Regarding other stuff, pika can duck under the lazers and shine. Pika is probably better at killing. He has nair, usmash and utilt (both can lead to thunder); less reliable are fsmash if youre not careful or fall into a bad situation, dair off stage and at high percents, and ftilt also at high percents, and god forbid you get hit by it but thunder2. Falco is definitely better at camping, although niether can camp the other very well. Regarding the illusion, I believe most aerials can go through it including nair. Some pikas might use skull bash. I like dair since it has a long attack animation, is powerful, and will cover huge amounts of the delay in time/distance. Its probably incredibly even without the chaingrab.