Current options on multipurpose lifters?

Murray said
A flat tappet cam will always be a flat tappet cam and a roller cam will always be a roller cam. You cannot mix the two because the design of the lobes on the cam are very different and they will self destruct if you play mix and match. Your choices seem to be, #1- do nothing and ignore the start-up noise, or #2- replace all the lifters with new ones.

There is a third option. You can try some of the oil additives like Marvel's Mystery Oil, Sea Foam and the like, though I've had little success with those. A few, not many. Certainly cheap enough to try, though.