Both players will be juniors this fall with two years of eligibility remaining. The signings leave BYU with one available scholarship, unless coaches award it to walk-on Craig Cusick, who played a significant role last season.
Rose told The Salt Lake Tribune on Tuesday that he has discussed the matter with Cusick, but that a decision won't be made for a few months.
Delgado, 6-2, helped the WNCC Cougars, coached by former Utahn Russell Beck, to a 26-7 record while averaging 18.3 points and 3.2 rebounds per game. He represented his native Mexico at the World University Games last summer, averaging 5.3 points and 2.6 rebounds.
BYU hopes he becomes the outside shooter it so desperately needs, after the Cougars shot just 34 percent from beyond the arc last season, their lowest percentage in Rose's seven years.
"Raul is an explosive and athletic guard," Rose said. "He's a skilled perimeter player and is an effective three-point shooter. He's an excellent defender and guards with great determination. We expect him to be able to guard multiple positions on the guard line."
The Bruins went 22-9 last season, with Ambrosino averaging 9.6 points and 5.3 rebounds per game. He shot 48.9 percent from the field and 43.8 percent from 3-point range.
Prior to playing at SLCC, Ambrosino played at Gulf Coast State College, a junior college in Panama City, Fla. He averaged 5.8 points and 2.8 rebounds.
"Agustin's an athletic big man who can really get up and down the floor. He's a skilled player and can stretch the defense with his perimeter shooting. He's versatile enough to play and guard multiple positions on the perimeter and in [the] post."
Rose also announced that Tyler Haws returns from his mission in the Philippines soon and will be welcomed back into the program. Haws averaged 11.3 points and 4.2 rebounds his freshman season before leaving on the two-year mission.