Something like “that” vs “those”
Something like “that”, things like “that”, “that” kind of, etc.
I often hear the above “that” parts as singulars even after many things were mentioned. But there seems to be the plural options. Any comments would be helpful.

For example,
This book is about vehicles such as cars, trains, airplanes or something like “that” (/things like “that”).
Q: Should/Could the “that” part be “those” because this part could refer to multiple vehicles?

You can do A first and next B, then C. Or B first, then C, B. “That kind of idea” would be good. “Those kinds of ideas”? or “That kind of ideas”?
Q: The “that” part could refer to some possible “combination”s” of A, B, C; then Should/Could it be “those kinds of ideas”? Or “That kind” could include everything (=singular?) Similarly, could the “idea” part be “ideas”?. How can I understand this?

Thank you.

Question

Something like “that” vs “those”
Something like “that”, things like “that”, “that” kind of, etc.
I often hear the above “that” parts as singulars even after many things were mentioned. But there seems to be the plural options. Any comments would be helpful.

For example,
This book is about vehicles such as cars, trains, airplanes or something like “that” (/things like “that”).
Q: Should/Could the “that” part be “those” because this part could refer to multiple vehicles?

You can do A first and next B, then C. Or B first, then C, B. “That kind of idea” would be good. “Those kinds of ideas”? or “That kind of ideas”?
Q: The “that” part could refer to some possible “combination”s” of A, B, C; then Should/Could it be “those kinds of ideas”? Or “That kind” could include everything (=singular?) Similarly, could the “idea” part be “ideas”?. How can I understand this?

Thank you.

Answer

"This book is about vehicles [such as cars, trains, airplanes] or something like that."
If I heard this sentence, I would take "that" to refer to an implied topic, that of the vehicles of various sorts. (But it should really then be written with a conjunction before "airplanes" and a comma following.) If it had been "things like those" (which is the plural of "something like that.”), it would be clearer that you are talking about the vehicle types. Similarly, in your next example,"that kind of idea" would refer to the whole arrangement.

Answer

Expressions such as "something like that" are stock phrases. You need not worry too much about the antecedents. I cannot provide a better explanation.