I don't know if an MBA would handle that very well. I don't have any third party synths to use. You can use multiple effects via bus assignment rather than new instances on each track.
There was a logic file you could download that had like 200 tracks of synths on it. The point was to load the file and enable tracks until your computer gives up the ghost. When I did this I got about 20 tracks. Powerful Mac Pro systems could handle 100-200 tracks. So a MBA a would not be a good solution if you are going to run 100 synths. For my persons, usage it works perfectly. I have 20-25 or so audio tracks with a few bussed effects and it works lovely.
There was a logic file you could download that had like 200 tracks of synths on it. The point was to load the file and enable tracks until your computer gives up the ghost. When I did this I got about 20 tracks. Powerful Mac Pro systems could handle 100-200 tracks. So a MBA a would not be a good solution if you are going to run 100 synths. For my persons, usage it works perfectly. I have 20-25 or so audio tracks with a few bussed effects and it works lovely.