If LE searched my home, they would find 4 or 5 of those knives (mostly without blades still in them) as well as 4 tool boxes and a cabinet full of tools, a kitchen drawer full of hundreds of paper receipts waiting to be shredded, coats, computer storage media, prescription pills, .........and hair dye.
I don't see much unusual in the list, unless the computer media contains some evidence, or there is some evidence on the pea coat, or some written evidence found.........or something more definate.
As to the fact that MR lived at home, this is a well documented phenomena known as "Boomerang Kids" and isn't at all unusual.
The statistics are that the majority of kids completing their University studies return to living at home. Others who joined the workforce in factory or construction jobs found themselves unemployed in the recession and many of those jobs have not come back. Woodstock has a high unemployment rate and few employment opportunities.
The high cost of student loans, cost of living........combined with high unemployment (and underemployment such as part time jobs) for this age group (some estimate it as high as 40% of the population, and with the addition of low wages.............has combined to create this scenario.
The parents of such kids are known as the "sandwich generation" squeezed between supporting their own aging parents and the return of their adult kids.
I wouldn't make too much of the fact that MR still lived at home. Most adults his age are doing the same.