1) Redundant read of same memory location. Just to be sure that there is no error in communication. Same at writing, write 32 bytes, then read them, and compare. Just to on safe side.
2) Scroll little bit down
Code:
'Optional Erase I2C EEPROM
    FOR Adr=0 TO 79999 STEP 128
        MAdr=Adr.WORD0
        MCtrl=$A0 + ((Adr.BYTE2 & %00000011)<<1)
     BootI2CW:
        I2CWRITE Mem_Sda,Mem_Scl,MCtrl,MAdr,[STR EraseStr\128],BootI2CW
        PAUSE 5
Just easy way to dump 128 zeros in memory.
3) Not sure what you are asking, but that is code for bootloader in main app. That code will sit there forever. And execute when jump to label.
Output of first 32 line from random project in MPLAB X program windows(right click output to file)
Code:
       Line      Address       Opcode           Label                        DisAssy                 
        1    00000         EF30                             GOTO 0x260                               
        2    00002         F001                             NOP                                      
        3    00004         FFFF                             NOP                                      
        4    00006         FFFF                             NOP                                      
        5    00008         0012                             RETURN 0                                 
        6    0000A         FFFF                             NOP                                      
        7    0000C         FFFF                             NOP                                      
        8    0000E         FFFF                             NOP                                      
        9    00010         FFFF                             NOP                                      
       10    00012         FFFF                             NOP                                      
       11    00014         FFFF                             NOP                                      
       12    00016         FFFF                             NOP                                      
       13    00018         0012                             RETURN 0                                 
       14    0001A         010F         HSEROUT             MOVLB 0xF                                
       15    0001C         0004         hseroutloop         CLRWDT                                   
       16    0001E         A89E                             BTFSS PIR1, 4, ACCESS                    
       17    00020         D7FD                             BRA hseroutloop
Similar thing you will get when compile bootloader, but at different start address. And you need to copy opcode column to to your main program and address must lineup.
I'm not sure that I answered your question.