yes, skilinked datajacks will work fine for DNI. you can plug data jack into fibreoptics and connect to commlink that way as well if you'd prefer. i believe trodes work just as well for dni
as regards commlinks, get the best one in the book. you can only upgrade them to +2 of the attribute so i think its the novatech airware and navi combination you need to be able to get the best upgrades.
if you want rating six commlink to start off with, then you need to get restricted gear and response 6. upgrade the system to match and get the best firewall you can.
tbh though, its a lot of cash, you might as well stick with R5 kit and software.
having your software at R5 means you can put program options in them (avail is too high for this @ chargen without restricted gear on R6 software)
so you could put mute on your exploit program and ergonomic on others to keep your response high.