Your understanding of the sentence is correct.
는 in 보다는 adds emphasis without changing the meaning. When 는 attaches to another particle, it has the effect of further highlighting the particle (it's like a contrast effect). It also tends to give a better rhythm to the phrase by balancing the words before and after it.
- 지난 번에 싫다고 했잖아? = You said you didn't like it last time. (sounds monotonous)
- 지난 번에는 싫다고 했잖아? = Last time around, you said you didn't like it. (sounds more rhythmical)
- 시골에서 여유롭게 살 수 있어요 = You can live leisurely in the countryside.
- 시골에서는 여유롭게 살 수 있어요 = In the countryside, you can leave leisurely.
As for -다고, it's a quoting suffix similar to "that" in English (친구는 바쁘다고 말했다 = My friend said that he was busy) . You attach it to the verb or adjective of a quoted clause. It is used not only for quoting verbal remarks but more broadly for relaying ideas and sentiments as well. 고 is sometimes dropped in certain formal sentences.
Your sentence 그는 지은 씨가 민지 씨에 비해 예쁘고, 밝다고 느끼다 is basically correct, except that 느끼다 is in the base form which is rare in normal usage. In most cases, it would be 느꼈다(past), 느낀다(present), 느낄 것이다(future), and so on.