Disclosure process 1: regardless of the result of the coin toss she will be informed it's Monday on Monday with probability 1

Under disclosure process 1, her credence of heads on Monday is still 1/2.

SB would start out with P(tails) = 1,000,001/1,000,002 and on being informed that it is monday would update:

P(tails | told monday) / P(heads | told monday)
= P(tails) / P(heads) * P(told monday | tails) / P(told monday | tails)
= (1,000,001/1,000,002)/(1/1,000,002) * (1 / 1,000,001) /(1) = 1

The initial strong belief in tails is cancelled by the strong evidence of being told that it is monday, which only happens in one of many wakings if the coin landed tails.

Disclosure process 2: if heads she'll be woken up and informed that it's Monday. If tails, she'll be woken up on Monday and one million subsequent days, and only be told the specific day on one randomly selected day.

Under disclosure process 2, if she's informed it's Monday, her credence of heads is 1,000,001/1,000,002. However, this is not implausible at all. It's correct. This statement is misleading: "It is, after all, rather gutsy to have credence 0.999999% in the proposition that an unobserved fair coin will fall heads." Beauty isn't predicting what will happen on the flip of a coin, she's predicting what did happen after receiving strong evidence that it's heads.

P(tails | told what day AND it is monday) / P(heads | told what day AND it is monday)
= P(tails) / P(heads) * P(told what day | tails) * P(it is monday | tails) / (P(told what day | heads) * P(it is monday | heads))
= (1,000,001/1,000,002)/(1/1,000,002) * ((1 / 1,000,001)*(1/1,000,001)) /(1 * 1) = 1 / 1,000,001

The initial strong belief in tails is canceled by the strong evidence of being told what day it is, and then updated further to strong belief in heads by the strong evidence of it being Monday.