[Lynne]

Part 1 - You are right, there isn't a way to specify that the field you created is for a date. However, there is an options to require it to "match a regular expression (PCRE)". I would guess you could force the users to enter a date in a certain format using a regular expression - like YYYY-MM-DD or whatever you want. (I'm not an expert on regular expressions though.)

Part 2 - I think that will have to be custom code. I am barely familiar with the calendar (I just don't use it much), but I'm thinking that you can grab the date at the time the profile field is successfully entered and then add something to the calendar at that point. You'd want to also make it so when/if a user changes that date, that the old one is removed, and the new one added. I can't think of any reason why this couldn't be coded.