1.If you use IC741 as comparator with Vcc=5V and -Vee=0 then for HIGH=4.5V and LOW=1.52, so in both condition transistor will be saturated, so in order to use IC741 as a comparator better apply -15,+15.

2. when LM324 is used with Vcc=5V then HIGH=3.6V(but this is the logic high for digital circuit) and LOW=0. So this will be better, you won't be able to get HIGH=5V.

3. In 741 when Vcc=5V,Vee=1.33V then HIGH=4.0 and LOW=0V. This is the reading which i got.

4. The best way of checking IC741 and IC324 is by using comparator configuration. But remember in checking case the input voltage to the comparator should be less than the supply voltages used. The output voltage will be some Vcc-2V and -Vee+2V at max.

5. You can used Vcc/ Vee to +/-9V at min for good response