I prefer Feuling lifters, worked great in my Buell to make it more quiet and put them in the Harley when I was in there. Not real cheap, but I think they are good quality.
Breathers are a given, they are cheap. Just make sure you install them the correct side up.
Like other people have said, just go ahead and install adjustable pushrods. You'll regret it later when you make a stupid mistake and have to go back in to fix it. Trust me, just buy them. I bought the lesser expensive S&S pushrods when I went back in to fix an O ring on the fuel pump that I didn't do correctly. Spend it now or spend it later, up to you.
I did not do a set of lockers, really should have done this but didn't learn about them until I had the top end buttoned up and didn't feel like going back in. I'll get there eventually.
Also... Depending on the mileage, go into the tank and change the fuel filters and check or replace the high pressure lines. Again they were fairly cheap for my 05, and I had to go back in to change the in tank to tank fitting high pressure line (output line) because of a leak. I went with a $25 third party line vs. the $60+ factory line. Another thing I should have heeded from the advice I was given, and didn't until it bit me in the @$$.