5.4l ford lean code and misfire cylinder 5

It's a 1997 expedition 5.4l getting a p0305 and the lean code escapes me right this second.  When the truck is at idle it's showing 21.1% ltft b2 that goes to 24% when rpm goes up. 

Bank two long term is definitely too high, but it'd be better to look at total trim on both banks to get a better idea of how the engine is running.

At your next opportunity, check out the short and long term values on each bank at idle and 2,500 RPM. Make sure your loop status is Closed.

Short term bank 1 + Long term bank 1 = Total trim bank 1
Short term bank 2 + Long term bank 2 = Total trim bank 2

At idle the B1 is ST 0.8 to -2.3 LT is steady 6.3
B2 ST 0 to -2.3 LT is 24.2

At 2500 rpm B1 is ST -3.1 to 0 Lt is 5.5 B2 ST -1.6 to 2.3 and LT is 23.4

So B1 would be 7.1 to 4% and B2 would be 24.2 to21.9% at idle and at rpms B1 2.4 to 5.5 and B221.8 to 25.7?

My downstream o2 sensor is dead i can see that causing the lean code but could that be the cause of the misfire as well?

Rear o2 should not be taking into consideration in dealing with the lean condition unless the front 02 is stuck rich while the rear, lean or vice versa.. Misfire will cause lean condition. Try moving everything from cylinder 5 to a cylinder in bank 1 and see if the weird fuel trims move with it.