Yes the pickup tube will work fine. Your dipstick can be changed but if you don't will read a little off due to some differences.
Am I missing something here? An ej205 is a USDM WRX 2.0. What is hard about getting a stock head gasket? I could have a set for you by tomorrw.... I think you are all thinking 207. Either way, the head gasket follows the BLOCK, you'll want the 22e gasket.
Not to disparage Walser as everyone I met there has been professional and pleasant, but in your case I would suggest Morries mtka. Erik (awdimprezal) is much more knowledgeable about custom builds than most people (let alone dealership sales reps) and would be a great resource for you to bounce ideas off of. If it were a simple "I need a gasket" type of situation, I'd say go to where ever is most convenient for you.
I appreciate the input idget. I have never dealt with any of the local Subaru dealerships so this is helpful. It's good to know that a member works at the Morries. Since this is just a "I need a gasket" situation and I know what I need I'll just go to the nearest one that offers our 20% member discount. haha
Erik (AWDL) was present for my entire EJ22T/WRX Heads build, as was Brian and Ben Peterson in the service department. They are all familiar with what you are doing and will be more than knowledgeable on the subject.