Its a very tough decision.. but I think you should go look at the boy and at Lola. You may just 'have a moment' or make a special connection that will make your decision all that much easier.
I have 2 boys. I LOVE LOVE LOVE boys! They are my world! They are sooo loving and cuddly and mammas boys! I don't think girls are quite as affectionate as boys but if you want a girl puppy then don't give up on what you want. 4.5 months is a long time to keep waiting for a maybe, BUT it will be worth it when you get what you want.
Im so sorry about your baby LeiLani. Thats so tragic and sad.