If, in the very unlikely event that the GOP-controlled House votes for articles of impeachment and sends the matter to the Senate for a trial, the only issue in that trial would be whether Trump committed "high crimes and misdemeanors" (presumably complicity in the Russia hacks, but maybe also conflicts of interest and conflicts of interest and other charges), If evidence also turns up implicating Ryan and/or McConnell in misdeeds, the situation is different. A senator can be removed is through the process of expulsion, which starts with a resolution referred to the Senate Ethics Committee. A House member can be expelled through a similar process, starting with a referral to its Ethics Committee.
In other words, if Trump goes down it is by no means automatic that he would take anyone else with him.
2. For vengeance, spite...call it what you will...
I'm betting the farm, he'll try to take everyone down with him...misery loves company and he's as miserable as they come. Losing Ryan would be a triumph for Wisconsin, there'd be dancing in the streets! Very quiet dancing albeit, as we're also heavily armed in these parts and some natives will be disturbed when their messiahs go down...not me tho!