假設語氣的倒裝句類型?

「倒裝句」和「假設語氣」完全沒有關係。
倒裝的目的在於藉移動句構順序來引起讀者對句子裡重要資訊的注意，所以有「強調」的功能，此外，語法上有「強制性」的倒裝，如「疑問句」或否定副詞在句前等狀況。問句在該倒裝而不倒裝時，會和直述句的「語調」的不同，此時，則語意可能就不太一樣了（有懷疑之意，不是單純的問）。如：Are you OK? vs. You are OK?

I will tell him if he is here.
= If he is here, I will tell him.
第二句因為副詞子句在句前（倒裝），所以必須加上逗號，表示主句在後。
這種倒裝有時是為了同段內後續的那些句子在舖路， 表示可能還有別的條件，目前所敘是條件之一而已。

Types of conditional clauses=three types of conditions:-
(1)Probable:-Supposing (that) I should  have  money, I shall buy a new house.
=Should I have money, I shall buy a new house.
---Conditional adj is upon and depending on a certain condition or conditions eg:-His agreement to buy the old house was conditional upon us leaving all the furniture in it.-------Probable
(2)Improbable condition:- eg:-If I had wings, I should fly.
=Had I wings, I should fly.
If wishes were horses, beggars would ride.
=Had wishes horses, beggars would ride.
Referring your posting:-If he is here, I will tell him.
=Were he here, I would tell him.
=emphasis special force given  to something to show that it is particularly important as an adverb  clause placed at the beginning of a sentence."Were he here" also means adding other necessary conditions eg:-and his money etc.
=Were he here.........Can you add certain conditions at the main clause ?eg:-would tell him the news.
(3)Impossible -rejected condition:-eg:-If English Tsai had come, the "party" should have been more successful
=Had English Tsai come, the" party" would have been more successful.
eg:-If the rocket had not been missled, we should have gone to the moon !
=Had rocket not missled, we should have gone to the moon !