Doubleday,
I do not have a kid playing at any of these programs, but I have watched them play a lot and know kids on each team. McLennan has a fellow Southlake player, Altimont, who could tell your son all about the Highlanders. Altimont and 6 other players signed with D1 programs this season. Facilities are the nicest of the 3 schools you mentioned.
Cisco has a reputation for having an extremely good strength program and kids come out of there transformed. They had a great year, but did not have the talent of Howard despite beating Howard in the Regionals. Their shortstop was a freshmen and led the team in most all offensive categories earning All-conference honors and more. Coach has been there since it's inception. They have a reputation for over recruiting. They bring a bunch of kids in each Fall and divide them into 3 squads. The squads scrimmage other JUCOs and D2 programs in the area. They select their spring team based on Fall performance.
Grayson had a down year and is looking to bounce back. They have a need for a good infielder with only 2 returning infielders. They have a great reputation. I grew up near Grayson and have watched the program since it started. Head coach, Dusty Hart, has led them to 3 National Championships. He was a shortstop in his playing days and knows the position. He has a great relationship with Skip Johnson of Texas and Tim Tadlock of Texas Tech, as well as many of the Big 12 coaches and programs.
Hope this info helps!