@Daniel_Bleich,
This is a completely understandable case! For this, I would use the progressive fields to capture your data. However, the solution may not be simple.
I would start with a multiple checkbox custom property of "A. Filling out for a partner, B. Filling out for a partner and customer, or C. Filling out for a partner and multiple customers.
I would then use the progressive fields to show the information pertinent to them. For A: show only partner information. For B: show end-user and partner information. For C: show end-user information and partner information. Add a text module in the form to let them know that if they plan on submitting more than one end-user information, they will need to submit end-user A, reset the form via the link, and enter a new form for each end-user. Although this seems tedious, it is around 30 seconds of work for each partner.
I would make sure to check the form’s setting and choose Always create for a new email address and add a link to reset the form. I tried the same exact thing with the default settings and ended up having to un-merge over 50 contacts over a period of 6 months. You do not even want to know how long this took me. I added the best form options below
If a partner sends you only a name and no email, phone number, or address and you have no way of contacting them, I’m not even sure why they would be submitting that and wasting both of your time…However, if this is really what you wanted, you could add help text to the email address and let the partner know to say firstnamelastname@noemail.com for example. Since HubSpot requires emails this would allow you to add a contact with a false email that will bounce. However, since HubSpot only relies only on the email address and the HubSpot Contact ID as unique identifiers, it seems like a waste. Especially since in Hub, you pay per contact.
If you have partners you work with on a regular basis, I would suggest them sending you a spreadsheet and importing it to save time and potential trouble. We have partners that send us 100+ leads per month, twice a month. I also have leads that I import 20 at a time based on different conventions, events, and partnerships. I can give you specific advice on this as well if you plan to go this route.
Sorry for the long response, feel free to reply if you have further questions or need specific help on your use case. I am happy to help!