How was FORKID used in Bitcoin Cash in the original point of the fork and in all updates since then?

References:

https://github.com/bitcoincashorg/bitcoincash.org/blob/master/spec/replay-protected-sighash.md

https://github.com/bitcoincashorg/bitcoincash.org/blob/master/spec/2018-nov-upgrade.md

It seems to me that in the original point of the fork, Bitcoin-ABC added an extra value 0x40 called SIGHASH_FORKID This has been achieved with the standard SIGHASH indicators to produce a SIGHASH byte that is incompatible with Bitcoin Core. This provides reproduction protection for all transactions that are signed with the ECDSA publication keys.

Questions:

Is the Forkid updated with each "protocol update", for example, the recent update of "Magnetic Anomaly"? If not, why not?

It seems that the May 2019 update will change the Forkid to 0xFF0001 but the specification mentions "The portfolios that follow the update should not have to change anything". — How is that possible?

Bitcoin-SV changed its Forkid For his recent fork hard away from Bitcoin-ABC? Is there any repetition protection between those two chains?