No effect on recipient

Well I would hope the recipient ends up having more carriers for oxygen afterwards than before - but apart from that, I aggree with Dharmesh.

Be careful because in blood transfusion we may have some side effects. However, in this case that you mentioned I thought that have no effect.

For most blood types we are typically concerned with the surface antigens and not the phenotype of the intracellular hemoglobins. That being said, if the hemoglobin you are transfusing has significantly different biophysical properties you may observe unexpected changes in the physiologic performance during transfusion. For example, human Hb in RBCs has a p50 ~ 28 mm Hg. If we replace that with a Hb species with a much lower O2 affinity (p50 ~ 50 mm Hg)we would expect a higher rate of O2 delivery resulting in arterioler over-oxygenation and auto-regulatory effects. In contrast if you are transfusing with another Hb that has a much lower O2 affinity (p50 ~ 10 mm Hg) you may observe hypoxia and other anemia like symptoms due to the loss of O2 delivery.

Any physiological effect would be so short lasting that it would be impossible to notice,

It will have no adverse effect but any hemoglobin variant will be diluted if the donor is wild type. If the donor carries a variant and the recipient is wild type, wou will find small percentages of the variant in the recepient.