Hi Foodfann - we are glad you found us, by whatever means.
We would really like to add alternative ingredients as a wiki. So members could add alternatives that are listed in the recipe (to be accessed by all members) or their personal variations (that would just be accessed by themselves). So it would function rather like private and open Notes. We couldn't have the Notes searchable for alternative ingredients as it's quite likely Notes contain references to ingredients that are not part of the recipe e.g. "I served this with steak" or "This bread was great with a lentil soup." So you wouldn't want those recipes appearing in searches for steak or lentils.
It's on our to-do list but I can't give you a date when it will be done.