Alloy nipples are fine provided the spokes are long enough. I've been using the same alloy nipples for the last ~15 years on one wheel set with one front rim replacement and at least two rears except for four I twisted with an incompletely seated spoke wrench getting a rim straight enough to ride home after bending it.

Anti-seize on the spoke threads will keep them turning for when you eventually wear out or bend the rim. An acid brush with the bristles cut down works. Lubrication of the spoke/rim interface is also necessary.

Any sort of spoke-prep which gets tacky to keep nipples from turning when the spokes aren't tight enough is a crutch for bad wheel building and going to do more harm than good with thin spokes.