Is this an example of a comma splice?

Yes.

Hi Yankee,

Is it incorrect or perhaps informal to write that way?

Thank you in advance.

Best wishes,

PBF

Hi PBF

It would have been better and correct to write two separate sentences (a question and a statement) or to reword the sentence like this, for example:
Hey, Paul, I would really appreciate it if you could send me a link to Greg's blog.

However, as is indicated by the "Hey, Paul", the sentence is informal and I doubt that the writer was particu

Yep. Okay. I see what you mean. Thank you Yankee.

Best wishes,

PBF