As we know, the CWC 2019 will have 10 teams. These were to be the host (England) plus top 7 teams in the ODI rankings on 30/09/2017. This was the ranking table on that date:
The first 8 (including the host) qualified while the bottom 4 (WI, Afg, Zim, Ire) would account for 4 places in the qualifying rounds in 2018.
They would be joined by the 4 top teams in the WCL championship. which got over in Dec 2017. These are the results:https://en.wikipedia.org/wiki/2015%E2%80%9317_ICC_World_Cricket_League_Championship#Points_table
Thus Netherlands, Scotland, Hong Kong and Papua New Guinea make up the second group of 4.
The remaining 2 spots will be selected from the bottom 4 in the WCL and the top 2 from WCL division 3: (Kenya, UAE, Nepal, Namibia) + (Canada, Oman).
There could be some upsets here, but probably Kenya and UAE will get through here. (Update: It was Nepal and UAE who emerged from this).
Details of this mini-qualifier (to be held in Feb 8-15 in Namibia) are here:
So we now have:WI, Afg, Zim, Ire, Neth, Sco, HK, PNG, Nep and UAE in the “main” qualifier to be held in Zimbabwe from March 4 to 25. These have been divided into two pools of 5. There will be Super Sixes but no semi-finals.
Now we see the ODI rankings as of today (Jan 16):
While there may be an occasional upset, it is very unlikely that the 2 qualifiers will be from the WCL teams. West Indies should have no trouble in qualifying, while there may be an interesting struggle for the other qualifying spot between Zimbabwe and Afghanistan. Zimbabwe may have a slight home advantage. Ireland has generally declined in ODIs over the past year and may not challenge the other three seriously.
Final update: It was West Indies and Afghanistan who qualified for the 2019 World Cup.