Lower palate. DNA appliance, Homeoblock, Biobloc, etc... Do they expand/widen the lower palate, too?

The answer to your question is yes. There is a DNA appliance designed for the lower arch. There are also other arch development appliances designed specifically for lower arch development and they do work. I use them every day in my practice.Good luck!

The DNA Appliance is a major breakthru for expansion of the maxilla.  It also works on the lower but the process is different.
The mandible will widen on its own some as the maxilla expands, at the same time there is relaxation of the medial pterygoid muscles as they no longer need to flex the mandible to fit inside small maxilla.
Will correct posterior lingual tipping and allow and  promote   anteriors to tip out.  
I advise also looking into Oral Myofunctional Therapy.  You have a marked bicuspid drop off on the lower arch secondary to as deviate swallow.
I would also suggest having a sleep dstudy done due to narrow arch.  Advantage is if you have sleep apnea your medical will pick up some of costs of mRNA version of DNA appliance that is FDA approved to treat sleep apnea.
There is a possibility of curing sleep apnea.
Do you also have TMJ issues, neck issues, headaches or migraines?

Ira L Shapira DDS, D,ABDSM, D,AAPM, FICCMO
Past Chair, Alliance of TMD Organizations
Diplomat,  Academy of Integrative Pain Management
Diplomate, American Board of Dental Sleep Medicine
Regent & Fellow, International College of CranioMandibular Orthopedics
Board Eligible, American Academy of CranioFacial Pain
Dental Section Editor, Sleep & Health JournalMember Cranio Editorial Board, Journal of Craniomandibular and Sleep Practice
Member, American Equilibration Society
Member, Academy of Applied Myofunctional SciencesMember, Academy of Cosmetic DentistryLife Member, American Dental Association