Thanks for writing to me, please note that the Horoscope Matching I do under my Paid analysis is very elaborate and is approx 4 pages of details between the two horoscope. It is a complete Guna milan and Graha Milan report, It is not possible for me to go into so much details in a free forum. However I can provide you with brief analysis here.
The Ashtkoot guna milan score between your sister and Umesh is 22.5 out of 36, you need 18 Guna for marriage. There is no dosha as such but Gharamaitri and Gana score is weak.
The Ashtkoot guna milan score between your sister and Raman is 25 out of 36, you need 18 minimum guna for marriage, however the boys 7th house has lot of affliction with Rahu, Mars and Sun. 7th lord Mercury is 6th house. Despite better Guna milan, the 7th house being the prime house of marriage and it being under affliction, marriage with Raman should be avoided.