I am not sure this is the best forum for sampling if your project is about the food industry!

There is no need to chase the elusive 'p<0.05' (particularly as p-values are meaningless anyway and such chasing typically ends up in the dubious practice of outcome-switching).

A thesis of 'negative' results is perfectly fine! It also makes for a more interesting discussion.

It would be helpful if ToL confirmed their discipline as there may be internationally recognised guidelines on authorship.

There does seem to be a lot of authorship snobbery going on here, as well as very odd reasons why this individual should/ should not be considered an author, such as:
1) They were/ weren't paid- no idea how this makes a difference,
2) Someone else could have done it (well, they didn't!)

For me... it's a no-brainer... they made a significant contribution to data acquisition, so should be given credit.

Reading pm133's post reminded me of the OP's statement about shoddy work and poor, simplistic arguments.

No requirement to be an ex-student to do PhD by published work at Warwick.

Carry on waiting!

Your supervisor is right. You are wrong!!

If this person is going to add value to your research through their ideas, knowledge, and experience- then you should consider seeing if they wish to collaborate.

If not, then:
- You are making any grant application more expensive (so potentially less fundable) for no reason!
- You are going down the road of 'gift' authorship- which is just wrong!

Presumably there will be administrative issues to sort if you move, which will take time.

If you are in your third year and take more than a week, it will likely be increasingly difficult, more disruptive and less beneficial to move.

A week seems very reasonable!

One option is to add an additional node for each piece of text with the speaker- i.e. create nodes of speaker 1, speaker 2 etc.

The funder has funded the research based on what was written in the grant application. The funder may well have not wanted to fund something with smaller groups.

You are conducting a feasibility study- larger groups presumably make sense from a cost-effectiveness perspective.
If everyone else has done smaller groups and it was feasible, there would be no value in doing a feasibility study.

If they meet authorship criteria- Yes (sounds like potentially they do)
If they don't - No. (but is it worth the hassle to not include them)