Signing 100 extra transactions using Schnorr signatures would only require an additional 6400 bytes of data. Even with a slow connection speed of 100KB/s, this extra data can be transferred in just 64ms, as latency is usually the main factor.

In terms of transaction fees, Replace-by-Fee (RBF) has a default minimum incremental relay fee of 1 satoshi per virtual byte (vByte). By using 100 pre-signed transaction variants, one can cover a range of 1 sat/vByte to 100 sat/vByte, which should be sufficient for getting mined in any block throughout Bitcoin's modern history.

On the other hand, Child-Pays-for-Parent (CPFP) requires two transactions and thus additional bytes. Unless there are specific edge cases involving very large transactions in low-fee environments, CPFP is not superior to RBF.

For more information on this topic, you can visit Peter Todd's website at https://petertodd.org or contact him via email at 'peter'[:-1]@petertodd.org.