What are typical airspeeds and lift coefficients for UAVs at different flight stages?
Observation UAVs are flown in a narrow range of lift coefficients. This can be seen from their wings: Like glider wings, they have a very high aspect ratio and a highly cambered airfoil. If you look at the optimum speeds for propeller and turbofan-powered aircraft, a high aspect ratio drives the optimum lift coefficient to high values which translates into a low calibrated air speed. Note that flying high does not necessarily mean that they operate at a low true air speed, however. Details depend on the altitude in which they are operated.

Let's look at the MQ-1 Predator for an example. Its aspect ratio is 19, and with all the protrusions I would guess the zero-lift drag coefficient to be no less than 0.025. This means the optimum lift coefficient for loiter is close to 2, which is probably above the maximum lift coefficient of the wing airfoil. For piston powered aircraft the best climb speed is identical to the optimum loiter speed, so the Predator should be flown close to its stall speed of 54 knots over the whole mission in order to get the most endurance out of this airframe. Note that the maximum g force the airframe can withstand is only 2, which means that top speed needs to be limited to 76.4 knots in order to avoid structural damage from flying into gusts.

Another giveaway is the low ground clearance of the tail surfaces: The predator lands at its regular flight attitude; there is no need to slow the aircraft down when it comes in for landing.

Short answer: The lift coefficient in all flight stages is high (0.8 to 1.4) while the true airspeed depends on the altitude. Turbofans tend to fly faster than piston-powered aircraft, but the difference is marginal.