LG Q6 Plus dimensions are 142.5 x 69.3 x 8.1 mm (W x H x D).
No. LG Q6 Plus comes with 1.2 A power charger which is not fast charger. But you can use Sony CP-AD2 USB charger to charge LG Q6 Plus faster.
Yes, you can change fonts in LG Q6 Plus.
Yes, you can change the font size in LG Q6 Plus.