I can only comment about Guangzhou. The cost of opening a WFOE is about 20k RMB in lawyers & other fees. The capital investment depends on the type of company and as noted above, has to come from outside China and can be in stages. You also need to have the lease already signed for your business premises before the process starts.
And then there is something affectionately called 'rent', that is needed to get some of the other certification required.
In fact you don't necessarily need a WFOE if you have a partner you trust or plan to export. I suspect you plan to export as I don't see much chance in the domestic market for differentiating tofu.
A middle way would be to open a new entity with a local partner and have yourself brought on in some management-like context with a revenue sharing arrangement written in to the contract. In this way your setup time decreases significantly (agencies can get you registered in a week or so for as little as 1500元) and you can still hang a visa off it, as long as you have specialty knowledge regarding the proposed operation. Licenses related to food will follow. For export, you will need foreign import licenses.
If you do want full ownership and formality, then IMHO (I've done it myself without legal assistance) you still don't need a lawyer to open a WFOE. They're not that hard, or expensive. What you may want a lawyer for is the food related permits. However, you can also get this information from the relevant government bureaus and it will not cost you anything.
A lot of the foreign community is a bit of an echo chamber, take everything you hear with a grain of salt.