We have a situation where we developed reusable workflows, content types and InfoPath 2010 forms for a client as a proof of concept but now the client has decided they can't go ahead with the ECALs for SharePoint so we're discarding the InfoPath forms in favour of custom ASPX pages. I'm pretty familiar with SPD2010 and InfoPath but not sure how to use custom ASPX pages. I have some skilled developers at my disposal to assist with the nuts and bolts and form logic as there is quite a bit of logic in the current InfoPath forms.
Basically what I want to achieve is associate the custom ASPX page plus code behind (required to complete form logic and querying a SQL database view for field population) with the content types we have created but I'm not 100% sure on how to achieve that goal?
The end result is to create a library, associate the relevant content type with it then when clicking on the Add New Item link, it must open the ASPX page where the user can complete the required details and submit the form/page which will then fire off a series of approval workflows etc.
From what I can find on the net it looks like we need to save the site as a template then import that template to Visual Studio and only selecting the required content type, create the forms and logic then republish the content type and forms back to SharePoint. It also looks like an Application Page is required due to the code behind needs which is then placed in the _layouts directory.
Is this the right track or does anyone have any better methods/suggestions?