It seems that Elvis introduces the Jackson 5 during his 5-26-1974 DS at the Sahara Tahoe, and his daughter is there as well. This totally helps pin down the date when any of the Jacksons actually met the singer.
And more.
The group was set to open at the Sahara the next day. At the time their newest single, "Dancing Machine," was #2 on the pop charts, and #1 on the r&b charts. It was a huge hit and a wonderful single.
..
Jackson 5 "Dancing Machine" ("The Sonny & Cher Comedy Hour," CBS-TV - Wednesday, January 30, 1974)
In Jermaine Jackson's 2011 book, he tells of how 15 year-old Michael and 23 year-old Jackie just happened to run into Elvis backstage, and now it is clear it happened during Presley's May 1974 Tahoe engagement. Given what Elvis says to them ("Good luck, fellas") it may well be from after his closing show on May 26th.
Jermaine Jackson, You Are Not Alone: Michael: Through a Brother's Eyes (New York: Touchstone, September 13, 2011)
Notice also how Jermaine does not recall that young Lisa actually met them. He was just told she came by. He must have been occupied with other visitors. In fact, she was brought backstage by Jerry Schilling and then-girlfriend Myrna Smith of the Sweet Inspirations after their opening show on 5-27-1974!
We attended a Jackson 5 concert at the Sahara in Lake Tahoe a day after Elvis had ended his engagement there, and after the show I introduced five-year-old [sic] Lisa to a teenage Michael Jackson.
Jerry Schilling - Me and a Guy Named Elvis: My Lifelong Friendship with Elvis Presley
https://books.google.com/books?id=9jn323M63PAC&pg=PT333
Jackson 5 at the Sahara Tahoe, May 1974
As may be seen below, the Jackson 5 were definitely booked to follow Elvis at the Sahara Tahoe starting on 5-27-1974, so it is no surprise they were in attendance at the 5-26-1974 DS, and got introduced by the singer. Interestingly, in May they followed Elvis, but at the same venue in October Presley followed them!
Elvis Presley - Sahara marquee, May 1974
Jackson 5 - Sahara marquee, May 1974
The summer entertainment season at the Sahara Tahoe promises to be a sizzler in '74. Heating things up to begin with will be the King Elvis.
A legend in his own time, Elvis created incomparable excitement every place he visits. Reservations for his 11 day engagement have already been taken but Elvis lovers can still hope for cancellations.
Following Elvis will be the Jackson Five, one of the most popular weekend attractions in the Spring.
Reno Gazette-Journal - Friday, May 10, 1974
https://www.newspapers.com/newspage/150750260/
The Jackson Five made such a hit two weeks ago at the Sahara Tahoe that they've been signed to follow Elvis for a week, opening May 27 ...
Reno Gazette-Journal - Friday, May 10, 1974
https://www.newspapers.com/newspage/150750283/
South Lake Tahoe
SAHARA TAHOE High Sierra Theatre: Jackson Five (Oct. 4-6), Elvis (Oct. 11-14), Ray Stevens-Kay Starr (Oct. 18-20), Bobby Vinton (Oct. 25-27).
Seating Times
SAHARA TAHOE: Seating in the High Sierra Theatre of the Sahara Tahoe begins at 5:30 for the 8:15 p.m. dinner show, and at 10:45 p.m. for the midnight cocktail show.
Reno Gazette-Journal - Friday, October 4, 1974
https://www.newspapers.com/newspage/148893193/
South Lake Tahoe
Del Webb's Sahara Tahoe has announced that all High Sierra Theater tickets have been sold out for the eight performances of Elvis in Concert, Oct. 11-14. Two traditions have been broken for the Elvis performances. The engagement marks the first time tickets have ever been sold for a High Sierra Theater show and there will be two cocktail shows nightly at 8:15 p.m. and midnight ...
San Mateo Times - Friday, October 4, 1974
https://www.newspapers.com/newspage/39069108/
Man, no one knew then what the future held, for any of them!
BONUS JACKSON 5
Jackson 5 at Lake Tahoe in 1974:
Jackson 5 in Las Vegas in 1974:Apr 26 - Apr 28, 1974 (3 shows)
May 27 - June 02, 1974 (7 shows)
Oct 04 - Oct 06, 1974 (3 shows)
Lake Tahoe, NV - Sahara Tahoe
http://www.jackson5abc.com/dossiers/concerts/
http://mjjtimeline.blogspot.com/2009/07/1974.html
Apr 10 - Apr 23, 1974 (14 shows)
Aug 21- Sep 03, 1974 (14 shows)
Nov 20 - Dec 03, 1974 (14 shows)
Las Vegas, NV - MGM Grand
http://www.jackson5abc.com/dossiers/concerts/
http://mjjtimeline.blogspot.com/2009/07/1974.html