Can someone be a "twice awarded Combat Infantry Badge recipient" from different wars (Korea & VN)?

Well I have two, One from Desert Storm, and one for OIF

Why yes thought everyone knew that

Yes

Also 2nd bn 505th PIR 82ND ABN DIV were awarded CIB for actions in Kosovo providence 1999. The award was issued in 2017.

Yes. Back in those warring states, it was more common than not that survivors of those hellacious conflicts were awarded a CIB per conflict. Today, not so much unless you fought in Just Cause, Desert Storm, the GWOT and/or an undisclosed location where you earned it.

SGM Basil Plumley (from “We Were Soldiers”) had three. WWII, Korea, Vietnam, along with a bunch of combat stars on his jump wings.

Short Answer: Yes
Longer Answer: Well yeah, that's why they make the CIB with stars on it, for additional awards.

Had a plt sgt who had a star he was in veitnam and iraq early on

I served with two. SFC Craig, my PLt Sgt In 1977 and COL Shacknow, my BDE Commander in 1981

If I am not mistaken their are periods for the award, the Vietnam era ended after the Panama Invasion. SO if you were from that Era, and then went to Desert Storm, yes, which is why you would have a CIB with a star above it.