Whilst you are understanding the costs, timelines and quantities, I'd look at all your options as you've listed. I agree with Debbie's suggestion.
Best to get a wide mix of prices and options and then focus in.
I've been an entrepreneur for years, but never in consumer product goods. I just recently started sourcing manufacturing directly from China and its been working well. Basically my process was to scour alibaba (aliexpress is too expensive) and then negotiated with them by playing them against each other. Essentially I took my product cost from 3.85 to .77 by going offshore. I would be willing to go over a step by step process to help you source the bottles.
If our call isn't worth the money I'll just refund you, no questions asked. I kinda just want to help you out because I'm interested in doing this more. I'll also give you free email support until what we talked about in the phone is accomplished.
Let me know if you want to chat about it more. Just shoot me a message.
My best -