Well, yes and no
You can use any strobe that uses a "slave" firing system, via fiber optic cabling or through sensing the flash in the water.
The Intova's are slaves, so they will work just fine... in fact you can use the fiber opitcs kit that Sealife uses to make it all nice and neat... but keep in mind the Intovas are "manual" flashes, which means you set the power with a button, and they don't work automatically like the Sealife ones theoretically do.
I could never get the dual Sealife Pro strobes to actually expose properly on automatic (always too blown out) so I just ran them manually anyway, so for me this would be no big deal.
The newer Intova model costs about half what the sealife one does, and when you order the strobe, base & kit the first thing you will see is that the base is made of metal as opposed to sealife's flimsy and (in my case three times) breakable plastic. The Intova comes with a diffuser, but the bases and cabling is extra.
As far as other brands go, if they can be used in slave mode then you can use them with your sealife cameras. If they require cabling that is anything other than fiber optic to operate, then they can't.