You can re use thermal pad i took my pi2 out and stuck pi3 in and temps are fine 1400 40-50c loads.
You don't have to remove case just stick piece of tape on end of SD card enough that you can pull it out
Has the flirc case been updated for pi3 meaning the LED placement or is it the same? Using my case from pi2 atm and its fine just noticed the LED not same as pi2 I was going to grab case from amazon but if its been updated ill get from this site....TIA