Could hashimoto's thyroid disease affect the size of a person's thyroid lobes? Thyroid sono showed mine to be slightly smaller than normal, overall.

Yes. Hashimoto's is a chronic inflammatory condition of the thyroid gland. Over time, the thyroid can become smaller and firm. This is not unusual for hashimoto's.
Yes. Hashimoto's can cause both an enlarged thyroid, also called a goiter (usually early in disease) or a small fibrotic thyroid (usually later in disease).