Modifier

1.The railroad employees are now seeking an expanded program of retirement benefits,added to the increase in hourly wages requested last July

2.Added to the increase in hourly wages requested last July, the railroad employees are now seeking an expanded program of retirement benefits.

3.In addition to the increase in hourly wages requested last July, the employees of the railroad are now seeking an expanded program of retirement benefits.

1. What is the role of past participle modifier in 1&2? Does it modify the closest noun?

2 In sentence 2 should we not have In addition to closer to retirement benefits rather than employee..Is it dangling here?

Thank you!