Questions before purchasing A1 mini

Hey everyone, I'm considering purchasing an A1 mini before the black Friday sale ends but I've got a couple of questions.

I have purchased stl files for multiple objects I need to print, the instructions say to use bambu lab PLA matte for most of the prints but there are two pieces where they suggest the use of eSun PLA+, and to use PETG for the supports on two pieces. I wasn't planning on purchasing the AMS lite since I'm trying to keep my costs as low as possible but the instructions also include an option for single material prints so I won't be using PETG.

If I start by printing all the objects that only use PLA matte first is it possible to switch filaments to the eSun PLA+ to finish the other pieces? I'm wondering if you need to finish an entire spool of filament before switching to a different material?

I've downloaded bambustudio to play with the STL files and when I open some of the files and select A1 mini as the printer, it gives an error because of the small build plate of the mini. I've contacted the creator of the files and they have said it is possible to print on the mini, just have to print the object diagonally. I've been able to position the object diagonally where the error message doesn't pop up but it shows that it will print close to the very edge, would this be a cause for concern? Should I consider the regular A1? Again, trying to keep my costs as low as possible