What takes precedence: an SPF record with "-all" in the primary TXT record, or one in the "include" section?
Assuming that all parsers adhere to the RFC4408 specification, the -all from the company.com record applies. The include does not modify the verification process, it merely expands it to include the mechanisms contained in the included record.
If you were to use redirect in place of include, like this for company.com:
v=spf1 ip4:70.70.70.70 redirect:host.marketing.com -all
the ~all would apply, and -all would be discarded in the verification sequence. That is, again, assuming that all parsers adhere to the specification