How easy (or difficult) is it to prosecute someone for Criminal Homicide under the?

'charge' of "Causing or aiding a suicide" ?

If there were a ton of valid evidences to support this case.....
would it still be extremely difficult?

What does the law require as 'proof' to make this kind of case plausalby 'stick' without reasonable doubt? What kind of stipulations are to this?

Also, if some one committed suicide as the result of another person's actions..... could that person be charged with either invoulantary or voluntary manslaughter as well, or instead of?

This is research of sorts...... could you provide case examples if possible?......

studies....................................

Unless thru direct evidence you can prove a substantive direct connection,it would be virtually impossible to charge someone as a party to a suicide. By direct evidence I mean physical evidence of a "direct" connection to the victim at the specific time the victim committed suicide. That is why there are laws that include several degree's of homicide and manslaughter. You talk of a ton of "valid evidences", but the fact remains that anything but DIRECT evidence is nothing but here-say and wouldn't even be allowed in as evidence in any court proceeding, in any court of law, in the United States.Even a fresh out of law school defense attorney could easy challenge and prevent this as being accepted as evidence.
I have explained it here to the best of my abilities. You are very vague in your information, so this is the best I can do without knowing more. If this victim was a family member I wish you luck in your efforts
Reasonable doubt is when a judge or jury decides based on the allowable evidence submitted, if in fact a party is guilty or not of a crime.

It can't be that hard, look at what happened to Dr.Jack Kavorkian.

It all depends on the evidence, and the ability of the prosecutor...evidence is either 'direct evidence' like the
proverbial SMOKING GUN, or indirect [ circumstantial] evidence like hearing a crash and finding a two-year-old
in front of a broken cookie jar. Both are admissible.
Something to remember: Innocent till proven guilty.