Boe, whose Maverick career ended in 2011, spent most of last season with Vegas.
"Channing made huge strides last year," coach/general manager Ryan Mougenel said. "He's a big body that makes good decisions on the blue line, and we need him to be an impact player for us to have success this year."
Cooper played nine games with the ECHL's Toledo, Ohio, team after the college season ended last spring.
"Cameron comes highly recommended from his college coaches," Mougenel said. "I look forward to him developing with our guys out here and proving to be another big body when we need it."
Schiller played eight games for Vegas after the Mavericks' season ended.
As for other MSU alumni ...
• Austin Lee will remain a Maverick, having signed with the CHL's Missouri Mavericks.
• Michael Dorr and Mike Louwerse signed to play in Europe, going to Germany and Denmark, respectively.
• Other recent signings include Rylan Galiardi going to the ECHL's Gwinnett (Ga.) Gladiators after playing last season with the Florida Everblades. Florida, meanwhile, re-signed former Mav Trevor Bruess.