I think you're on to the right idea. Fill flash is pretty much a necessity in bright light if you want to properly expose both the sky and the foreground. There are plenty of ways to go about this, but personally, here's what I do: I use spot metering and meter on the sky. Then I set the flash to a power setting that, by experience, I think is close to the right amount of light to properly expose the foreground. Shoot a test shot, check the results. The sky should be properly exposed, so to adjust the exposure of the foreground, I can pump-up the flash's power. Alternately, one can open the aperture to increase the flash exposure, while compensating by stopping-down the shutter speed. However, in daylight it's easy to bump into the flash's max-sync speed; that's when a 2 or 3 stop ND filter can come in handy. The GN of a flash falls off VERY quickly when in high-speed-sync mode (I've only once been able to effectively use my 580EXII in daylight at 1/4000, and they're the most powerful flash available from Canon.

).
The bigger problem to overcome is that the first picture needs
lots of fill. Hence, it would be useful to have two flashes with umbrellas to the right and left to fill-in the scene; that way one could get more, and more even light.
#1 is okay, but the flash is too direct. Would have been better bounced off the ceiling, with a gobo to block direct light on the cake. There are also multiple colour temps; looks like you needed a 1/2 or full CTO.
#2 needed more ambient light (higher ISO or shutter drag) and less flash as fill to get rid of the uneven exposure.
#3 is very underexposed. If it's not in RAW that can't be reasonably salvaged. Again, it needs more ambient. A shutter speed of 1/30, or ISO of 800 or 1600 would not go amiss.
#4 Motion blur like this can look cool, but 1.1s is too long for this movement. 0.5 would be the upper limit for me. This could have been accomplished by reducing ISO to 200. Furthermore, again, the flash needed to be gelled to match ambient lighting; something around 1/2 or full CTO.
#5 Timing is good, exposure is not. Again, you need shutter drag; at least another stop of light would help matters. 1/30 would have been a better choice. Higher ISO would help matters as well. Bouncing flash off the ceiling with a bounce card attached or 80-20 would not go amiss, to lift shadows of the groom blocking the light (this is something one has to anticipate and thus have the bounce card out or 80-20 on before one starts shooting the dancing). Flash will also help to stop motion, even at 1/30, but having a higher ISO and keeping the shutter speed the same would be preferable (letting the flash
really stop motion; ISO 1600 and 1/60 would have likely worked nicely, or at least brought the image up a stop, into the realm of recoverability in RAW).
#6 Compositionally I find it appealing, but the hanger outside the curtain on the left I find distracting, as well as the blue plaster wall at the bottom. The image is also quite hot, and could have done with about 2/3 stops less exposure (or even an HDR with well-restrained tone-mapping). The image is also quite noticeably noisy. In this case shooting with a tripod and increasing exposure time to get down to ISO 100 would have been a good option. As it is, putting it through DeNoise or even a simpler noise reduction algorithm like that in Lightroom or Aperture will likely resolve the noise issue, though getting the cleanest image in-camera as possible is nary always preferable.