IF you wind up changing cams to something other than stock, then you will need to determine if the new cam has the same base circle diameter as the stock cam. If not, then a pushrod length change will be necessary. Also, IF you change cams, then I would most definitely change the inner cam bearings to the full complement type used in the '13 and later CVO's. That should not affect your ESP coverage, as Harley itself now recommends the higher capacity bearings.
As for the lifters, either the standard S&S or the Premium are highly recommended by a whole lot of engine builders. I don't think you would go wrong with either. The jury is still out on the upgraded lifters Harley installs in the 2013 and later CVO's, with reports of failures showing up on those as well. It may be necessary, as others have mentioned, to start considering lifter replacement at 20k mile intervals to be part of normal maintenance, no matter what brand you use. The problem is more than just the lifters (but the original Harley lifters didn't help), it seems to be more of a complete system problem. Changing lifters every 20k is cheap insurance compared to an engine overhaul. Of course if you plan to keep the ESP in force you will need to factor that into your decision as well. No one can say with 100% accuracy what an ESP inspector would do if you had a failure and he noticed non-standard lifters. My gut feeling is he would disallow the claim.
JMHO - Jerry