64GB memory is very rare in laptops for some reason but you made right choice to start looking at gaming laptops. They are ugly as sin, but at least you don't have to pay for overpriced and largely useless (for CGI) ECC memory and Quadro professional GPU cards.
Beware of displays. In gaming, the recent trend is to go all out with 144HZ fast panels, and to achieve that, they often sacrifice display quality and only go for TN panel, or VA panel at best, IPS is lot more rare. Even expensive gaming laptop will often give preference to speed&latency at cost of pure visual quality and accuracy, latter being lot more important for work.
Btw, good to have the model which 1070/1080 Q-Max or Non Q-max with 8GB VRAM on the GPU. I found that viewports in CGI softwares run out of GPU memory very soon and then basically lag heavily.
Checked the ROG swiftly, it does have G-Sync 120HZ display, but nowhere does it say what sort of panel it is. I would research that. High price is never a warranty of high-quality display in gaming laptops.
Yeah your External drive should would fine, though I don't know how it connects. Moderns non-Apple laptops have both Thunderbolt and USB classic and USB C-port.
