Ignoring the outdoor/garage stuff, I would want to know a bit more about where the speakers are placed in the family room and address that independently from the rest of the system.
A surround receiver is really designed for one room, not for distributed audio, but if your new receiver supports multiple zones, then it may be fine to use for the other speaker locations.
Ideally, you would be looking for a speaker which supports frequencies from 20hz to 20Khz. That's not realistic, unfortunately, so a 8" 2-way or 3-way design is far more common, which is why you got the link for the 8" speaker above.
Now, when you have the picture of the family room, for some reason there are two speaker holes that appear to be side by side. I'm just not sure if that's correct and mirrored on both sides or what is going on. It almost looks like it may be a stereo setup, with a 12" woofer and then some other speaker for the other hole. So, perhaps a 12" woofer, and a 8" 2-way would work in those locations. Weird, but it may work and be acceptable at a budget price. Crossovers would be... tough.
I would recommend taking a look at 2-way and 3-way speakers. Most raw drivers are just a single speaker that is designed to go into a speaker box, and used with other speakers, so finding a single coaxial speaker which isn't just a pre-fab in-ceiling model is going to limit your options. Especially today, when 6.5" speakers are most common, and there are just a lot less 8" speakers, but they are common. 12" size is just unheard of.
Do not dispair my friend!
Parts Express is a good place to look for speaker building components. And that's really what you are looking at and talking about. They have speaker components, you can break down into a number of different sizes. From small speakers up to 12" diameter, full-range.
So, not really cheap is going to be an issue, because what you want to do is not really normal:
https://www.parts-express.com/celestion-ftx1225-12-coaxial-full-range-professional-driver--294-2098
At 10" and 12" they only have 4 options each, and only one of which (linked above) was a true full range. The jump at 8" is significant, where you have 31 choices.
Which then makes me wonder if you want to rework things a bit, as part of the project, to just used pre-fab in-ceiling 8" speakers. There is a long line of available 8" speakers that are both 2-way or 3-way in design.
I certainly would spend a bit more on things in the family room than outside or in the garage.
As for outside and in the garage, I'm not fan of Pyle (cheap, cheap, cheap), but they will certainly work just fine. If you are happy with the audio, then who is anyone to tell you otherwise.
The problem now is that you bought a one-room surround receiver and you have 3-rooms. I really wish you has asked before that purchase, because I think that's the single biggest limiting component in your system. It can't run volume separately to the outdoor speakers. You have a total of 7-channels of amplification, designed for surround sound, but you have a total of 8 speakers, running all in stereo. So, you can see that it is a problem. Are you within a return window? I'm serious about that, because at the moment, you really can't run the other zones separately, in any way, from the family room.
At the very least, you are looking for a pair of amp channels which can drive zone 2/3 separately, with fixed or independent volume control.
You could pick up a external amplifier for the other speakers, and run a speaker selector/volume control to run them. That would be under $200 and may be easier than returning things and may provide more stable power to the other speakers.
http://www.ebay.com/itm/SONANCE-SONAMP-260-MKII-2-CHANNEL-POWER-AMPLIFIER-EXCELLENT-/371926176408?hash=item5698871298:g:HnUAAOSwVm5Y-R74
and
http://www.ebay.com/itm/NILES-SVL-2-SPEAKER-SELECTION-VOLUME-CONTROL-SYSTEM-/311834322395?hash=item489ac625db:g:IYkAAOSwB-1Yr2dH
This will only support analog audio (red/white audio RCA jacks type) for your outdoor speakers. Most CD players support this, and the headphone jack on your computer can be used to push out analog audio.
Like this:
https://www.amazon.com/3-5mm-Stereo-Plated-Auxiliary-Splitter/dp/B01LW2R2P1/ref=sr_1_1?ie=UTF8&qid=1493052725&sr=8-1-spons&keywords=3.5mm+to+rca&psc=1
You aren't way off, but there's a few things to consider. The 40+ year old custom in-ceiling speakers are certainly an issue because they go against all current designs and will definitely be a project to address properly.