Responding to Simon Krughoff's comments:
- I don't have access to LDM-465. Does that really need to be private?
LDM-465 doesn't exist; the document has been renamed LDM-472. Unfortunately, Docushare just throws a permission denied error. As of this ticket branch, DMTN-020 refers to LDM-472 (https://dmtn-020.lsst.io/v/DM-6447/).
- Out of curiosity, what does the 'L' in LDM, LSE, etc. stand for (LSST?)?
The official glossary (Document-11921) lists LDM as "archive handle format for LSST data management subsystem controlled documents", and similarly for LSE, LPM etc. It doesn't say so explicitly, but I think it's fair to surmise that it stands for "LSST". I also think that's out of scope for this note! 
- What is the distinction between a scientist and a senior scientist? Same question for developers? Is it salary, or seniority?
As I understand it, it's just salary – at least as far as we're concerned, these classifications are only used to set the BCWS by estimating total cost without listing everybody's individual salaries. Jacek Becla or Kevin Long, please correct me if you disagree.
- Under EV and PP, it says "It has two members of staff – A and A". Should be "It has two members of staff – A and B".
Already fixed on this ticket.
- Defining epics – I think we should also say that an epic must have a team assigned and should have a label.
Team: you mean this as a general principle, or as a requirement for ingest into PMCS? I agree with the general principle, but I think we need to add more teams (e.g. for external collaborators).
Label: I don't understand this requirement. Why?
- Defining Stories – I think it is too strong to say all stories to be worked must be defined before the sprint starts. We would like that to happen, but there will sometimes be urgent emergent work that must be done in the middle of a sprint. This is mentioned later, but may be worth calling out here.
Good point. I was trying to say that you shouldn't go into a sprint with ill-defined goals, not that it's impossible for urgent work to emerge while sprinting. I've added a note to clarify: https://github.com/lsst-dm/dmtn-020/commit/72d43aabb65e508a97201c72a72209ffc5229e88
- In Handling Bugs & Emergent Work --> Scheduling: I don't understand the first sentence "must be immediately by adding". Should it be "must be done immediately by adding"?
Yes; good catch. Fixed.
Thanks for comments! I think some of them have actually already been addressed (were you looking at the ticket branch – https://dmtn-020.lsst.io/v/DM-6447/ ?), but I'll check. I'll fix up the others.