You have 26 turns? I guess that's what they give you on easy. I usually have between 8 and 10 turns each time.
As for Transoul, it's mainly for raising your level cap for your units. Eventually they'll hit their limit, and you'll either need to transoul someone into them if you want to keep them and continue to raise their level, or them into someone else so that another unit and continue to level up. You also get a VIT and stat boost for it (and possibly level gains!). Just make sure their LOY(altiy) is high. Just for the hell of it, go into the transoul thing next time, and when you hold down on a unit, hit the digital pad. You'll see a stat growth chart. Some units have a nice steady incline of growth, while others hit a high point and taper off. Just remember, even though this should be obvious enough, transoul causes the unit losing the soul to... wait for it... DIE. So yea, don't do that with someone you planned on keeping.
I don't know about provided units. It may be different on easy, but on normal I usually get someone to help, but not every time. But the game even says if you don't have many knights, it'll provide some nameless ones for help.