The DA and MDA's have something to do with the 500ft tower on 3 DME mile final which is probably only 2 miles from threshold...

For instance: You are on the ILS and at about 3 DME you would be VERY close to the tower on glideslope. However, If you are on the localizer look closely to the profile view. You are only allowed to decend to 840 ft at that tower location (step down fix) then after the tower you can decend to MDA. This is just an obstacle clearance issue.

The second question is just speculation on my part because I've never seen that before but it could be this.

Look at ULESS. It says 183 degrees for 7.3. That is the distance to the localizer course on a 183 Mag Course. The 4.5 could be the distance away from the Localizer directly to it possibly.