My first recommendation would be to quilt it yourself, second would be to tie it yourself. Are you sure you can get it longarmed in time to meet your deadline? Where I am good longarm quilters always have a backlog of 2 or 3 months work, especially at this time of year.
The easiest way for you to quilt it yourself would be to use a walking foot. With that, you can just make big curvy lines from one end of the quilt to the other without worrying about staying in the ditch or keeping lines perfectly straight. If you do it both up-down and side-to-side, you have curvy crosshatching. However, I have some tips that would help with this, so read on.
Bearding is not caused by the type of machine that does the quilting, but by the type of batting you use. All-polyester batting is the worst for bearding, although nowadays some have resin coatings that delay or prevent bearding. If you want the fluffiness of poly, my recommendation is to get Hobbs Heirloom 80/20 (80% cotton, 20% poly). Cotton battings do not beard and, in my opinion, hold up to frequent washings better than poly. The lovely vintage quilts we all admire were made with 100% cotton batting. It holds up to wear!
If you decide to tie the quilt, I would recommend using Warm n Natural cotton batting. This batting is needlepunched through scrim so it will not beard and is very stable. The stability of this batting allows tying or quilting fairly far apart (I wouldn't go further than 6 inches apart, but theoretically you could go 9 or 10 inches apart). Many, many quilters use this batting exclusively because it is so fail-safe. I personally don't use it anymore because I find the drape somewhat stiff compared to non-scrim cotton battings. I want the soft drape of vintage quilts.
If you decide to machine quilt, I highly recommend starching the backing fabric heavily before layering. This prevents puckers and tucks underneath. I use a 1:1 solution of liquid Sta-Flo laundry starch and water, lay the backing on my kitchen island, "paint" the starch on using a large wall painting brush, throw the saturated fabric into the dryer, then iron with steam. This makes a nice stiff backing that won't pucker when you machine quilt. If you use a cotton batting, you can then spray baste the quilt sandwich together in a few minutes rather than pin basting or thread basting (both of which take a lot more time). Spray basting doesn't always work well with polyester batting, especially if the backing has been starched.
Years ago I made a baby quilt for my niece using 100% cotton batting (Mountain Mist Blue Ribbon). I happened to see the quilt again about 15 years later, after her mother had run it through their washer and dryer about a gazillion times, and it was the softest thing you could imagine! The colors had faded to a gentle vintage look, the binding was frayed from use, but the feel of it was like hugging a cloud! My niece takes very good care of it now.
Hope this helps get you started!