yes with ES4 you should be able to do all of that. it depends on how you plan to distribute the forms to the audience.
via email, through a hosted link, or through the Adobe livecycle mobile app.
For such a simple use case, you would most likely not require the forms manager.
you will need mobile forms, which means essentially the capability to render HTML5 form.
this form should have a submit button, which could send you back just the data XML (containing the fields data).
Such a form, when submitted through mobile or desktop devices, should be able to submit XML data to your webservice, or LC process, which can then merge the data again with your form design and render to save the complete doc as a PDF.