I’m having all the same issues on no reverse.
Gen 2 with one day old shift cable !
Everything looks good with new oem parts.
I think the gearcase shift shaft has to move to far to get reverse.
I took the shift spool out and the crank and clutch dog cross pin. Pin has slight wear , crank looks...
I replaced my transom cable on my mercruiser 350 magnum.
I did have reverse .
I have put many outdrives on boats .
I can’t get reverse either manually or connected
To the plate and adjusted to 6 in on center !
I’ve put the new shift slide and a new roller
Lever that sits in the forks to move...