Dropshippers shall not add products from alibaba, because alibaba was built for the B2B business. You will face these problems and risks if the products of your shopify store were imported from alibaba.
You may price your products too low.
The prices on alibaba are fake. The prices are not the final one. It does not include the fast shipping fee and the taxes. And the prices there are for bulk orders. If you buy only a few pieces, the last price you get will be much higher than it looks like.
There is no stock available.
It is not a B2C marketplace, products on alibaba mostly were not produced yet, there is no stock available. Because the factories there are targeting buyers who want to buy in bulk and who can wait for the mass production. If a product is available on alibaba, while it is not on aliexpress, it either means the product is quite new or it requires huge moq.
Source from aliexpress, instead of alibaba!