I think with 2 hours if that is their only 2 events then you should be able to do that fairly easily. Make sure get a good cool down in and then get some food(protein) in between and then obviously need to be warmed up good for the 2nd event.
Overall I think doing multiple events is pretty common and not that hard, what we do is we don't really ask our kids to do it a ton through the season but we'll experiment with 2-3 events as needed throughout the year. Then if at the state meet 4 events is called for they will be excited to get it done.
Have had a girl split 2:09 in the 3200m Relay, PR with a 4:49 in the 1600(won), run 2:12 and win the 800(a few tenths off open PR) and then split 56 in the 4x4. If your athletes are trained right and ready to run good races, and they take care of themselves on that day, they should be fine.