Lightning Related Lists: Have a few questions:

• I saw an idea for having more than 4 fields on a related list on desktop and the PM commented that would be coming in Summer.  Is that still true?
• With that being said I'm super excited for this - how will we define which shows up on mobile and which on desktop or if we configure 10 on desktop all 10 would show on mobile?
• Inline editing on related lists, I thought this was a thing, but it doesn't seem to be working for me, is there something I need to turn on or is that not a thing yet and we need to build custom?  If not a thing, then will it be a thing and when?
• On a related list we have a requirement to show a total of records/total of currency field, anyway to do this without building a custom component?