I have a UT2 with a regular metal strap button and it fits in the case with no modification. It is very TIGHT and I have to put the upper bout in first then grab the back side of the case and pry it out while sliding the bottom of the uke with the button into the case. The padding at the upper bout is very compressed like that. I do wish they would have made it a bit longer.
My UC2 is very, very tight. I would not feel comfortable trying to squeeze it in if it had a pin or pickup socket. I was thinking of bringing it to a luggage repair guy and have them route out a section where the pin/pickup would fit and then replace the cloth lining. I was just wondering if anyone else did something similar.