This is my solution to magic the sword would have a magic req of 75 and would only train magic it's spec is a miasic barrage that can hit 60 s
For second part u can set a spell to auto cast but it will only always be cast if u are far away if u are close it will either attack with melée/ magic or magic/ magic and if u chose a spell maualy while attacking it will cast it on who ever u are attacking it cab also auto cast vangence and veng other when ever it can pluse it could do spell book switch