How does the map go for TTS production and audio editing?

I mean, you have a tun of voices on the mac so you should be good. I personally when I do this, use a app called say it, on the appstore, to export the files, although it can be done as well via terminal if you wish, I just prefer that app myself. If you want to use other voices from windows, set up a vm and install the voices you want, and set up a shared folder from your mac to your vm to put the voices dialog, files in and your good to go. I don't know what's your prefered audio editor of choice, I myself use reaper, but there's also amadeus pro, amung others. As far as it working better on a desktop or laptop... I'd say laptop, as the desktop, limits you as in, you cant carry it with you everyware as you cann with a laptop, so I'd say stick to your macbook air. Hope this helps!
Oh also, if you have a audio database or library, you can get samplism for this.

I'm sure there are better ways but, the way I do it is I paste one file after the other in my daw. Like, if voice 1 says hi, and voice 2 replies hey there, I have both on their own file, like voice 1.wav and voice 2.wav, and then I just paste them one after the other and move them if needed. I'm pretty sure voices have tags or a way to switch from voice to voice 2 in say it or the macb but I don't know how. I just manipulate the audio files individually.

What you can do is you can download them from freesound.org that is waht I usually do. Also I use an audio edditing software called wavepad.

As someone who composes music, I use Logic along with Native Instruments software so it is good.

There are various resources to get sounds, freesound is one, as someone said, or there's the itunes store, you can find a lot of great sound libraries there, i.e, Hollywood edge, premier Hollywood, sound dogs, pro sound effects, etc, and most of them are $10.
I'm also a composer, however I use reaper instead of logic, but yes, I do use native instruments as well.
As far as your daw of choice... I have used amadeus pro, pro tools, logic, though this last one just barely, but point is, that's up to you. All of the above, barring pro tools, do not and I repeat; do not; go for pro tools, as there are way better daws out there to pick from, plus they are way; way cheeper. But yeah, as far as which audio editing software, daw, to use... that's something only you can decide. Although rule of thumb, or just as a general piece of advice... don't go for pro tools. If your starting out with audio editing, i'd recommend amadeus pro to get you started as this one is simpler and easier to get the hang of. Or reaper. Reaper does have a steeper learning curve, but its well worth it. I cannot speak for either logic, as I barely used it... Well, I did, but just never got the hang of it, to be honest. Its way too complicated from what I experienced, and wavpad as I don't have experience with that daw either. I cant stress this enough though... don't go for pro tools. Again the, don't go for pro tools is my own opinion from personal first hand experience, and others here might say otherwise, but I for one wouldn't recommend it do to the price, the cheepest version is $110 per year, and yes, its only subscription, that, amung other things don't make it worth it, but that's for another post. However if I had to give you advice as to which daw to get... I'd suggest reaper, as its fully accessible on mac and on windows, if your going to rely on both systems, but if your just staying on mac... amadeus pro would be a good option as far as getting started with audio editing do to its simplicity and easy learning curve if your just getting started.