How to automate document creation from form input, convert to PDF, and get signatures?

I’ve been working on this for days and can’t seem to figure it out. Maybe it isn’t possible.  I’ve read tons of articles and community posts. I’ve also tried several other services (plumsnail, PDF.io, DocuSign, DropBox Sign) and every time I run into some kind of roadblock that prevents the process from continuing. Here is the process in outline form (I’m not married to any of this - I just want the end result): 

1. New client fills out webform (right now a Google form)
2. Input data from the form populates {{replacement_tags}} in a template (right now a google doc template called Agreement_Template. The newly created document is named Agreement_client’s_name and saved in a separate folder called Client Agreements)
   • Some data is raw conversion: {{name}}=Name
   • Some data is conditional: if project A - {{fee}}=$925, if project B - {{fee}}=$850, etc.
3. That new document needs to be converted to PDF (every document will have a unique name)
   • I think I can trigger on “new file in folder” with that new folder being Client Agreements mentioned in step 2.
4. That new PDF gets sent out for signature via some e-signature system. 

I have step 1 & 2 working smoothy. I’ve even recreated the same form-to-document process using Plubsnail.  However, I constantly run into a wall either between steps 2&3 or between steps 3&4.   

I can create a new document from form data but I can’t convert it to PDF….or...if I can convert it to PDF I can’t get a signature system to pick it up because it wants to use a template and every document is based on different data (same form just different results). 

So frustrating to figure this out.  Oh, I’m also on a budget.  Adding $25/month service here and a $10/month service there to accomplish one step adds up quick. 

Thanks for your help.