What is the preponderant opinion and the saying of the majority of scholars regarding the layman when scholarly opinions differ on an issue? Is it permissible for a layman to follow the easier fatwa as long as the scholar is trustworthy? And if that is not permissible and he follows it, does the fatwa become void, or is he only sinful?

It is obligatory for an ordinary person to emulate the scholar he trusts most. If they are equal and none is more distinguished, it is said: he may choose; and it is said: he should take the more stringent opinion; and it is said: he should take the easier opinion. It is not permissible for a person to habitually follow concessions. However, if one takes some concessions from scholars due to necessity, there is no harm. So, if you emulate someone you trust, and he gives you the easier fatwa (definition), your action is correct and there is no sin upon you.