Simulink for Amplitude Modulation
1) Do I fail to understand the question? The allowed frequency range of a bandpass filter goes from Fpass1 to Fpass2. The range between Fstop1 and Fpass1 and from Fpass2 to Fstop2 is the transition range where the filter goes from fully attenuated to fully "open" so there shouldn't be any strong interferers in this range.

2) Your band select filter before the down-mixer. It usually has your carrier frequency in the middle of Fpass1 and Fpass2 and is as wide as your expected signal is.

3) 999000