I would say no.
I think the problem lies in that "很少人，很多人，每个人，没有人" are all indefinite, and a topicalized indefinite nominal structure sounds extremely strange to me as a native speaker.
Sentences 1 & 3 are perfect whilst sentences 2 & 4 sound weird.
However, at the same time, I can accept &...
如是者 seems to be a modern day Cantonese phrase:
so; so that; in sequence with the above mentioned
你而家開始一個月儲三千蚊, 如是者, 三十年後你就夠畀首期。
You can try to save $3000 a month from now on, so that you can afford the down payment after 30 years.
I'd treat it more as a set phrase rather than as its individual components.
Pursuing profoundly, delving the depths,
not eating or sleeping,
thusly for years
one day good hap, characters of The Tale of the Three Kingdoms sprang to mind，
without thinking, it suddenly dawned on me, I yelled：
an ancient hero,
profound and secret, that's ...
this word like 'ah','um' kinds of words in English ,so my answer is ,it does not have a exact meaning ,but just for the rhythm ,which means you can also delete it and the sentence still makes sense .
this sentence means (i do things )like this having years .and we can look at its original mean :会意。字从耂从日。“耂”字从土从丿，读为“不土”，义为“不耕土”；“日”指“日子”、“每天”。“耂”与“日”联合起来表示“...
穷索冥搜，忘寝废食，[如是(者)]有年 = searching earnestly, to the point of not sleeping or eating, and [like this (way)] for years
如是(者) = like this (way) --> "way" refers to " in the manner of (穷索冥搜，忘寝废食)"
You can see '者' as the pronoun for 'the not sleeping or eating way of search'
他日间工作夜间读书，十年如是 = he works at day, study at night ...
I want to ask if you can do the same for quantifiers - 很少人，很多人，每个人，没有人 for example.
I'd say yes. A topic doesn't need to be a proper noun, it can be a statement of any kind.
"Few people" is ...