most sololane champs can go either mid or top if the matchup fits.
most mages are actually decent bot as either carry(casio, victor, vlad...) or support(brand, vel, lux....)
Most adc can do well in a sololane
However, for all 'off roles', the main issue is the overall composition. Toplaners can tell you that vayne is perfectly capable of bulling any melee 1v1 in lane at prettymuch any point in the game. But she still tends to loose games cause her team lacks beef and/or CC and simply gets run down in teamfights, while she is to vulnerable to ganks to bring it home with splitpushing alone.
As far as jungle/sololane goes, there are not that many left, it used to be alot more.
It also depends on what elo you play. If your good at a champ, you can make it work in about every role in lower elos.
At high elos, you eventually reach a point where everyone is good at the champ they play so you can't compensate a sub optimal pick through skill anymore