As MPC8306RM.pdf shows, one can multiplex some pins such as, LAD8/GE_PA0 multiplexing. My design uses LOCAL BUS (nor flash) and UTOPIA at the same time. Can I design my product like this in view of pin multiplexing?
LAD8 must be used as local bus pin. For UTOPIA, this pin serves as PA0, which is UTOPIA TX address 4. Usually this UTOPIA signal can be not-used.
MPC8306 Reference Manual chapter 184.108.40.206 states that LAD [0:15] can carry both A [0:15] and A [16:31] via ABSWAP setting switching. How can I use it to skip LAD8 to address local bus device?
ABSWAP is not used dynamically. It should be set either 0 or 1 but not be switched from time to time. In this case only A [16:31] (from LAD) is available when ABSWAP is used (set to 1). In this case this can only be used if customer requires 16 bit or fewer address lines.
In MPC8306, for UTOPIA pins UPC1_RxADDR [2:4]/UPC1_TxADDR [2:4], each signal has two pins described in MPC8306RM. Based on this, can I use any one of the pins LAD08 or MDVAL for UPC1_TxADDR ? For LAD08, I'll assign this pin for LOCAL BUS.
Yes, you can use any one of the 2 pins for these signals using PMUXCR register. UPC1_TxADDR  can be either the one multiplexed with LAD08 or MDVAL. You can assign LAD08 pin for LOCAL BUS.
Also remind you that, UPC1_TxADDR 4] is MSB, if only 4-bit UTOPIA address is needed, just use UPC1_TxADDR [0:3] and this LAD08/UPC1_TxADDR pin can be configured as LAD08 by clearing PMUXCR[QE1] bit to 0.
In MPC8306, I saw that LOE/ LGPL2/ LFRE in the same line, but in P1016EC.pdf, only LGPL2 is present in B14-pin description and I cannot find LOE/LFRE. Can LOE/LFRE (GPCM read enable) signal use B14-pin?
LOE/LFRE (GPCM read enable) signal can use B14-pin. For LGPLx pins, we only put the LPGLx in our hardware spec. You can find all other multiplexed function from MPC8306 reference manual.