Only bit 7 of OPTION_REG control the weak pullup on portB and only on portB.

When :

OPTION_REG.7 = 0 the weak pullup are set

OPTION_REG.7 = 1 the weak pullup are removed

Naturally the pullup apply only if portB is an input, otherwise if is set as an OUTPUT, you don't need any pullup.

If you need a pulldown situation, on portB, then you set OPTION_REG.7 = 1 and you connect external resistors from pins to ground.

Al.