Hello,
before I dwell into the particular details of the project, I do have a major question in regards to the functionality of the templating system (i.e. the interactive first part, where a user builds the PDF template). Did you mean that the generated PDFs would be fillable PDF forms, because if that is the case, you will need full Adobe acrobat license running on windows machine, in order to use their form building API... Hence it would not be feasible to build such application given the listed specs.
That being said, if it's just "visual" template, which you will be somehow able to bind data with, e.g. call field "Company_name" and then somehow merge the data and produce populated PDFs, that shouldn't be an issue; however it'd be great if we knew exactly how much flexibility you need in the templates (i.e. different formats and paper sizes, images and their location, other objects...?)
After I have the information above, I should be able to better assess the requirements of the project, in terms of technologies, time, and budget.
Let me know if you want to have a chat about it in more detail.
Thanks for your consideration.
Kind regards
Simon Vlcek
CGE LTD