And Shain V’Regel should not be, etc. - ולא תהא שן ורגל כולי
Summary:
The exclusion of כספו applies only to payments of מגופו but not מן העלייה. We can derive from צרורות that even מן העלייה there can be payment of only a ח"נ. If there is a choice between two ק"ו we would utilize the one which is stricter regarding payments.
And a person should be liable for ransom - ויהא אדם חייב בכופר
Summary:
The פסוק of לא תקחו כופר teaches us that we cannot accept כופר in lieu of מיתת בי"ד. The גמרא here wants to derive that he should be killed and pay כופר. The תנא דבי חזקיה merely compares שוגג to מזיד, but does not rule whether there is a liability or not.
Summary:
The פסוק of ולא תקחו כופר actually teaches us that עין תחת עין means a monetary payment. The גמרא mistakenly assumed that it is discussing ממון אחר בהדי מיתה, but the גמרא never assumed that it comes to exclude that we do not kill him and make him pay כופר, for that is derived from עליו.