Well, I decided to test out an auto-zoom feature, using the wonderful Magi-Cam plugin, and much to my surprise, despite some fiddling to make everything work correctly and look fine, there wasn't any seams appearing in the tilemaps, and the pixelation from the zooming was actually rather not too bad, it's noticeable, but reasonable.
I did have to unbound the scrolling to make it work right, though (meaning, the scrolling moves outside the layout) but I implemented a masking effect of sorts which blacks out everything outside the layout, and a simple border around the layout, which basically establishes the arena's boundaries, and should hopefully make the players focus on what's in the layout and ignore everything else. The automatic zooming takes into account every player that's active at any time.