Indeed. Same rule applies to one hundred (hyaku) and one thousand (sen), but not after ten thousand (ichi-man, ichi-oku, i-cchou, etc.), except in the intervals between every 4th zero like in the first set (juu-man, hyaku-man, sen-man, etc.). I love Japanese.
Yes. In most European countries even small parties can get seats. In my country there are 8 parties in parliament, for example, and 2 of them didn’t use to be there 2 election cycles ago (they were too small/new 8 years ago but eventually grew in popularity and got enough votes for representation).
Of course if they only have 1 or 2 members in parliament they typcily tend to form coalitions with other like-minded parties so they can get more voting power.