Edit contribution form with PCP-linked soft credit is not loading correct values and fields

When editing a contribution that has a soft credit linked to a PCP page, we should be displaying the pcp block section of the form AND loading values for the 3 pcp-related fields saved values (e.g. pcp_display_in_roll etc.). Currently we are not doing this (see Coleman's screenshot - PCP.png for current wrong behavior vs. new screenshot I just posted from 4.3).

The Contribution View page should also display PCP-related saved field values when contribution_soft has a non-null pcp_id value.

NOTE: Although it is technically possible to store both a PCP-linked soft credit and other soft credits (as indicated by Coleman below), we haven't had any requests for that and it would add complexity to the UI that may not be necessary. Let's leave this 'binary' for now (either 1 or more 'regular' soft credits OR 1 PCP-linked soft credit).

=== original post ===
The new multiple soft credits UI has an odd interaction with the personal-campaign-page selection.
For one thing, choosing a PCP prevents you from adding any additional soft credits. I don't think there's any good reason for this.
For another thing, your choice to set a pcp gets reverted in case of a formrule refresh.
But the really odd bit is that when you edit an existing contribution that is linked to a PCP, the form makes it look like it is not linked to a PCP, and prompts you to add one.
Screenshot attached of what it looks like when you try to edit a contribution that has a PCP.