"Overo" means nothing at all, I wish people would stop using it. It is a hangover form the days before genetics when all the patterns not Tobiano, were lumped together under this heading because people could not tell them apart, for some reason!
Splash/ Sabino/LWO are somewhat similar but quite easy to tell apart. LWO should be tested for at all times, especially if the horse has Rowdy in the pedigree, before breeding. It is the only fatal in H/Z pattern. In h/Z form it is harmless.
The real problem comes with the fact that Splash and Sabino are very rarely seen separately so they tend to get lumped together.
Tobiano is quite often seen on it's own- it does not have face white or blue eyes- but, in Minis, all bets are off as all the patterns are mixed indiscriminately.
If we could also ditch "Tovero" , which as far as I can see is only used either in ignorance or to bump the price, as in "rare Tovero" my world would be complete!!