You're probably right. I got the feeling Perisic was our first choice too however I don't think Atsu factors into it while as much as I think he should play on the left it seems he's been bought as Deulofeu's replacement.
However they aren't the reasons the OP said was the cause of us not getting Tadic. He said that it was because of Lukaku and if that is the case then the board have set a very limiting and rigid figure for Martinez to work with especially with all the new money coming in.
I was the OP haha! I don't think Martinez wanted to risk it mate - but Tadic was a target. But we've spent £32 million so far this summer, plus new contracts for Barry, Coleman etc.