I agree. As much as Lassiter hates seeing a guilty person go free, he also can't see innocents go to prison. I'm sure he was relieved when he saw Shawn jump on the case because as he put it in Earth to Starbucks, Shawn's abilities bring a "guaranteed arrest"- he always figures it out.
The bike thing at the end was just a token of appreciation. Unfortunately for Lassie, it didn't go off as "undercover" as he wanted it to, lol.
And yes, I do also believe that the two of them have a deep respect for each other. Shawn doesn't mind showing it- he knows the SBPD needs Lassie, which is why he helped him out in Earth to Starbucks. Lassie openly showing his respect for Shawn, well...he's just Lassie