FYI, Kyle Katarn only plays a minor role in LOTF and Jaden Korr is not present at all in LOTF from what I recall. If he does show up, its a mention. Crosscurrent gives you more of what Korr was doing during the events of LOTF than the actual series, though even that is probably a page at the most of recollection/reflection. However, that page explains a lot of his motivation in Crosscurrent.
Katarn plays even less of a role in the first five books of FOTJ. Korr only got one brief scene in FOTJ so far. So, I wouldn't get too amped about either series if you expect to see a lot of Katarn or Korr.
In fact one of my major criticisms of both LOTF and FOTJ is the poor use of the Jedi Council and other Jedi besides the Skywalker-Solos. The Jedi Council dithers way too much in both series.