Log cabin quilt block
 

Sure. You'll just get a bigger block.

Absolutely yes. Actually, I took a class as a new quilter and they recommended starting with a jelly roll

Sure can. In fact I've made JR quilts with 2" strips.

Eleanor Burns makes her log cabins with 2.5" strips. I've made two quilts using her method.

Yes, you can. Made one myself when I needed a quick gift. Here is the free pattern from Jordan Fabrics that uses a jelly roll (2.5" strips.) https://jordanfabrics.com/pages/jelly-roll-log-cabin

I made a log cabin quilt using six 1/2 strips. I was in a hurry.

My next project planned is a Log Cabin Quilt and this thread caught my eye. I'm planning on using the 2.5" strips as well. I have Eleanor Burns book, 'Make a Quilt in a Day Log Cabin Book 6th Edition' and her ruler that goes with it to make the cutting quicker and easier. I like the idea of using the 2.5" strips for making the bigger blocks. It will end up being a 14" block, finished size, though I might add another round to make it a 16" block finished size, if I have enough 2.5" strips of the lights and darks. I'll be making a king size quilt.

We’ve used the EB method to make 2 queen/king “ish” sized quilts. Here is the last one we made. The block finishes at 14” so you get a bigger quilt pretty fast.

https://www.quiltingboard.com/vbulle...t-t313580.html

I don't know how I missed this one. It's gorgeous and the backing is perfect for it.
To the original poster, yes, I've made LC blocks with 2 1/2 inch strips.
Show us when you finish!