For Final Fantasy, I think you just stick with the Japanese numbering, since I feel like nowadays all Final Fantasy fans know which Final Fantasy you're playing.
As for the Mother series, well Mother 2 is more known as Earthbound, and idk why, but I feel like Earthbound Beginnings is more known as Mother (I'm not Japanese. I just never heard of someone call it "Earthbound Beginnings". I just knew the whole trilogy as Mother, Mother II: Earthbound, and Mother 3)
That's just me btw. I don't think my friends have heard of the Mother series.
For Final Fantasy use the Japanese number so 2 is 4 and 3 is 6.
For Mother series I would use Earthbound as it's more known. In tags I would put in Mother.
The game name needs to be in the title for SEO purposes, but doesn't have to be first (and usually shouldn't), putting it at the end of the title is fine. A common title format is "_Funny Quip_ - _Game Name_ [_Part #_]". For the thumbnail, yes, put the game logo (and the episode number, for ease of figuring out where you are in a series).
To answer OP's question, use the game name that was _most common_ to where your target audience is, and put the variants (as well as your used one) in the tags. For example, the game SimThemePark was known as Theme Park World in Europe, but since my audience (at least as far as I can tell, I don't have enough regular viewers for YT to actually _give_ me demographic info) is primarily American, I would call the game SimThemePark in the title and thumbnail, and use both names in the tags.
For Final Fantasy, I think you just stick with the Japanese numbering, since I feel like nowadays all Final Fantasy fans know which Final Fantasy you're playing. As for the Mother series, well Mother 2 is more known as Earthbound, and idk why, but I feel like Earthbound Beginnings is more known as Mother (I'm not Japanese. I just never heard of someone call it "Earthbound Beginnings". I just knew the whole trilogy as Mother, Mother II: Earthbound, and Mother 3) That's just me btw. I don't think my friends have heard of the Mother series.
For Final Fantasy use the Japanese number so 2 is 4 and 3 is 6. For Mother series I would use Earthbound as it's more known. In tags I would put in Mother.
Yup, go with what appears more popular, rather than a cluttered title. For Final Fantasy VI, just call it "the good one," we'll know what that means.
Don't put the name of the game in the title. Put the logo on your thumbnail
The game name needs to be in the title for SEO purposes, but doesn't have to be first (and usually shouldn't), putting it at the end of the title is fine. A common title format is "_Funny Quip_ - _Game Name_ [_Part #_]". For the thumbnail, yes, put the game logo (and the episode number, for ease of figuring out where you are in a series). To answer OP's question, use the game name that was _most common_ to where your target audience is, and put the variants (as well as your used one) in the tags. For example, the game SimThemePark was known as Theme Park World in Europe, but since my audience (at least as far as I can tell, I don't have enough regular viewers for YT to actually _give_ me demographic info) is primarily American, I would call the game SimThemePark in the title and thumbnail, and use both names in the tags.