Will the new hair may grow slower and avoid needing trimmed?

There is no evidence in recipient dominance.  If you have scalp hair transplanted to the eyebrows, it will grow like sclap hair.

Eyebrow transplantation consists of the dermal extraction of hair follicles –which are genetically resistant to thinning- located on the posterior scalp between the ears, and the dermal transplantation of these follicles on the site where you want eyebrow hairs to grow. The transplanted eyebrow hairs do not fall off, and the result is permanent.
Eyebrow transplantation is actually a kind of hair transplantation. Hair follicles are used in eyebrow transplantation. Eyebrows are made to grow by transplanting hairs in the place of eyebrow hairs.
Similar to hair transplantation, two methods can be used in eyebrow transplantation in order to extract hair follicles. These methods are FUT and FUE.
FUT method is not generally preferred in eyebrow transplantation operations. This method requires an incision on the posterior scalp and sutures. The thin but permanent scar it leaves is the most important disadvantage of this method.
On the other hand, hair follicles are individually extracted from the posterior scalp by the FUE eyebrow transplantation without making any incisions or sutures. This procedure leaves no permanent scars.