Clarifying Questions About Clay, HS Integration, and Tagging Features

We have been always gathering form submission in Clay either via webhook or importing lists from HS. We would enrich these contacts, update them in HS, and then push a message to one of our slack channels. We noticed in one table that aside from the new entries individually every of our past submissions also get pushed to slack. Any idea? For example we had slack messages coming during the weekend at the same time. Could it be that by enabling auto update on the HS update column whenever the contact gets enriched and updated in HS the list that Clay pulls in would also get updated and then the whole batch would get pushed because of the updates? Creating one loop?! Assuming that we got the whole batch message in slack around the same time I have a feeling that it is tied to the daily update that happens on our HS import column.

Is there a way create a column where we can have multiple "tag like" values? Like the select type of column but with the addition that multiple select can happen. Example: contact would be a part of 2 different type of campaigns and we would like to add these "tags" in one cell

Connecting to point 2. Is there a possibility to have a select type of column where the selectable fields would get updated by the values of a specific column? Example: Column A is a text column that is written manually. For our sales reps we want to build a select column where they can easily select values but we would like to automate this so that the team does not have to add the options manually