preparation for the arrival of ray pups?

gd day guys,

my female is preggy but i have no idea which stage she is in now, but
recently i can see obvious movement, mummy ray is still eating like
a cow, so i think she might be weeks away to deliver.

current she is with 1 male ray(daddy), 9 aro (10-12"), 3 erh,
1 IT, 1 albino pleco and 1 iriwin catfish (spelling), all in a 6 x 2.5 x 2.5
tank.


i know at this stage to move the mummy its very dangerous hence
she has to deliver the pup(s) in the current 6ft tank.

hence i plan to standby a small basket to contain the pup(s) when
they are out within the tank first. also, planning to standby a 4ft fgt
(at least 4x2x2) to transfer the pups (and maybe the mummy for her
recuperate).

questions:
1. immediately giving birth the water in the tank will be very dirty, can
perform WC immediately or can wait for a while first but how long?
2. can i removed the female ray and pups immediately after deliver?
3. jialat situation is the deliver took place when i m at work and no
at home to separate the pup(s), how
4. lastly, anything i missed out or any bro/sis have any input pls feel free.

thanks in advance

JD