Because this quilt is important to you (sentiment) I would find a longarmer that has a longer frame to quilt it. I would not dismantle parts of it and hope to get it back together after it is quilted. Besides that——-look how long it took to get it together the first time.......you don’t want to take that long to reattach everything.....and who will be quilting that part???
You can continue to trade with your friend on other projects. Pay for this one. An edge-to-edge will be reasonable (especially for the size of this top).
Speaking from experience: I had some borders I did not like after I had quilted and bound a quilt. I cut them off and re-bordered, quilted and bound the edges. It was a major feat to do this but here’s why I would not do it again.....the quilt does not hang straight....did not look so good hanging in a show. Not worth the hassles.