2 Books I would recommend, both by Sharyn Craig, are "Setting Solutions, and "Great Sets". If you don't want to purchase them maybe your local library has a copy.
Your grandmas blocks are fantastic. Before sewing anything together, I would trim them to all the same size as I noticed the fraying around most of them.
I think they are screaming 'on point', however you can add triangles to each corner to make they look as they are straight set. Make your triangles a little larger then trim them all to the size you want. It's really easy to do.
You have an eye for design by the look of the items you posted above. I do not think the Irish Chain is above your skill level. Take it slow and square up as you go. You shouldn't have any problems. You Can Do This! You are making wonderful memories you can cherish forever.