Line of Scrimmage Rules?

[Official]

So basically the way I understand it. You can have seven or more guys on the line. To be an eligible receiver you can't have a number 50-70. The two outside receivers on the line are eligible. Anyone on the line inside the two ends are ineligible. What about this formation. I would say WR4 is elible since he's on the end. WR1 is eligible since he's on the end of the line. WR3 is eligible since he's of the line. I'm confused about WR2 and TE1 can somebody explain their status?

WR4----------OOOOOTE1---WR2------WR1
-----------------O--------------WR3