Maybe a crinum? Which one I have no idea, but maybe you can find it in this list?

If you have some roundup and put some in a plastic container that you can dispose of later and some rubber gloves, soak a cotton ball or several in the roundup and paint it on the leaves of the burdock. By applying the roundup in this manner you don't risk spraying other plants that you want to keep and you will kill the root of the burdock. Just make sure you don't drip any roundup on anything else.

Lactuca, wild lettuce, of some variety, I think.

I'm at least glad that you planted according to the root flare depth and, as j0on03 said, chopping out the girdling roots will pay dividends. Subjectively, I prefer a more natural arrangement. It appears that you planted yours in pretty much an equilateral triangle. If you are going to be planting that many trees you might "shake it up a bit." Obviously the windbreak would be more functional if evenly planted, but the property can look more park-like if alignments, spacings, and even initial sizes within a group of the same species are varied. It makes the scene look like the seeds were blown in and grew where they fell. And a last thought - that may be an external workshop, but it is on a concrete block foundation. As strong as bur oak wood is I wouldn't be too worried about a branch crunching the structure for a LONG time. But as the red oak pic below shows, over time oaks have powerful roots. Planted 8-9' away from the patio about 17 years ago... hortster