Node-"Basket" with Flag (needs custom field, date field?)

Hey Folks,
I'd like to establish something like a Shoppingcart for Nodes of certain content-types.

The Flag-Module seems to be a pretty nice way to get this done (I haven't worked with it before), but with some restrictions... but maybe someone can help me to solve these issues. The workaround should be:
1. Anonymous User or logged in user can collect nodes by flagging them (works fine with Flag 2 and Session-Api so far)
2. Before he can Flag something he needs to select a Date with the calendar widget, some select-fields, and maybe he should also have a Custom Text-Field here... Is there a way to add custom fields like these ones to a Flag?
3. Maybe I'll need a way to have several Flags on one node, with different dates then. Is that possible?
4. Use can see all his flagged nodes in a block (I guess this could be done with Views, without a problem)
5. After User is finished, he can "checkout": He get's a final View of his flagged content, he can change date/time etc. here, can delete flags, etc. He types in his Name, Telephone whatever and get's registered as a user for the webpage, or can log in.
6. After this, all flagged content should be used to create nodes of a "request"-Content-Type. I guess this can be handled with Actions??

My main issues are:
Custom Fields for Flag?
Several Flags for one node?
Dealing with the checkout?

The workaround here is obviously like a webshop, but I don't want to setup a whole ubercart for this, because there is no payment-stuff etc. It's just for collecting requests.

Maybe some could help me with some cool ideas...