Many many questions about the meaning of bold-faced phrase

Many many questions about the meaning of bold-faced phrase

The passage below is from Fathoms: The World in the Whale Hardcover by Rebecca Giggs.

A few days after we all returned home, one of the participants — a woman from Ontario, whose academic field was theories of walking — phoned with alarming news. A microbial guest had climbed aboard her during the retreat, an amoebic

parasite called Dientamoeba fragilis, most likely gleaned from the dam. Over the next week, we all came down with symptoms of this common, single-cellular pest; we suffered abdominal pains, had medical tests, were prescribed strong courses of antibiotics—which we then met with various probiotics and tinctures, sachets that were whipped into a salty froth and swallowed hastily before bed. A member of our party, being pregnant, was told she had to wait to be treated until after she returned, notionally, to living as a single organism, with only one heart beating inside her.

After camping trip, all members of the camping returned home with parasites, so they got treated with antibiotics.

No problem. So far, so good.

But after dash, I cannot get what the author is trying to convey.

First, what does the ‘which’ represent? It is antibiotics. Am I right?

Second, the usage of verb ‘meet’.

What I find in dictionary only shows ‘meet with something’ but this sentence, I think, is ‘meet something with some other things,’ that is, met (which=antibiotics) with various probiotics and tinctures, sachets.

Am I right?

If that is right, then to me the meaning of ‘meet’ can be ‘mix’. Am I right?

Third, but meanings of various words.

To me,

‘probiotics’ seems to mean ‘some tablets for gut health’ (since they suffer stomach pains).

‘tinctures’ to mean ‘some drinks for gut health’

‘sachets’ to mean ‘some tablets for gut health’

‘salty’ to mean ‘pungent’

‘froth’ to mean ‘foam’

Am I right to give meaning to the words?

Last but not least, what ‘that’ stands for in ‘that were whipped’? Is it for only ‘sachets,’ or for ‘probiotics and tinctures, sachets’? (To me it seems to represent the latter three medicines. Am I right?)

So people having the camping trip together, all have to get some tablets, drinks, and pills mixed, and whipped into a pungent foam, and drink it quickly before bed.

Am I right?

Thanks in advance.