Whichever matches the symptom. If the Google Business Profile never appears in the map pack, start there. If organic traffic is flat across the whole site, start with the SEO diagnostic. Diagnosis before commitment is cheaper than the reverse.
Yes. Each is a standalone engagement with its own scope. They combine well, but nothing here is sold as a bundle you have to take whole.
No. Rankings belong to Google. We commit to the work: defined deliverables, on a schedule, reported honestly, including the months where a change produced nothing measurable.
Every engagement opens with a fixed-price diagnostic, quoted before it starts. Ongoing work is quoted after that conversation rather than from a price list.
Often, and it is usually the better arrangement. We write the specification, your developer implements it in a codebase they already know, and we review what ships.