Leaving links to policies and documentation is tricky: If there is a lot of it, it might be intimidating. Generally speaking it would be better to feature these links at a prominent & relevant location on your site, eg. on the edit page.
Point 3 does imply that you’ve checked their recent activity - this is important so you avoid wasting time “welcoming” a spammer or vandal.
Oh and watch their page for replies! New users probably don’t know how to reach you. This is usually not a problem for founders doing the welcoming. But for bigger distributed efforts, this is crucial.
Notes on the importance of homepages: