The tight points on your steering mat be the universal joints on the steering column, there are two in the engine bay, These can dry out and rust, they don't cost much to replace. You can test by spraying the joints with loads of WD40, this may free them up, but is only TEMPORARY and doesn't fix them.
Before you spend money on a rack rod, it could be worth temporarily removing the bracket on the diff to see if this stops the rattling. If this does turn out to be the problem I would check to see if it is a standard track rod, as if a thicker one has been fitted, that could be the issue.
This bracket isn't essential as it is not fitted to Discovery and Range Rovers that use the same axle. It is there because the rear track rod is vulnerable for being bent backwards when the axle grounds whilst off roading, the bracket is supposed to prevent this, but in practice the rod just bends around it.
Before you fit up-rated parts, it is worth considering that when you add strength in one area, it moves the weak link to a different and possibly more expensive part of the chain.
As far as smoke on start-up is concerned, the smoke may just be un-burnt fuel if it took a while to start. I used to have a perfectly healthy 2.5N/A that was a reluctant starter from cold, unless you used the heater plugs and that smoked like a good-un on initial start-up.