Which is correct.
Dan thought it would make sense for me and Val to attend training.
OR Dan thought it would make sense for Val and I to attend training.
Which is correct.
Dan thought it would make sense for me and Val to attend training.
OR Dan thought it would make sense for Val and I to attend training.
The first one is correct. As the subject is “it” and verb is “would” and I in object always become me. you could alsowanted say “ dan and I though it would make sense for me and Val...
The first sentence is the correct one. You should use the object form of self "me" as the object of the preposition "for".