I have no experience on fitting fenders or mirrors. Mirrors say No but they Don't say Yes, so bear that in mind when you're turning or pulling out and always turn your head and have a look as well.

Unless you have hundreds to spend on lights I would shop for 4V or 8V rechargable cree lights on Ebay. You can get one with a 4Ah battery pack for around $18 US and at that price you can buy 2 or more and have spare batteries. I have been using them for years with no failures but be careful to get all the same voltage or you might blow one as I did. https://tinyurl.com/j35hzk9



Definitely look into the flooring of that trailer. You mightn't carry more than a toddler in weight but a toddler doesn't have sharp edges like some recyclables do. (don't they have bins where you live)

You will need some flat tire solution unless you're happy pushing the rig for miles? CO2 cylinders or a pump and some patches say.

Lastly scope out the touring sub-forum, the hybrid forum is more about cycling for pleasure and what you are doing is more business like. Lots of trailer discussion in the other one I am sure.

PS: It often helps if you include things like your Location in your profile. "out there" sounds cool I must admit, but it won't help with specific advice and will exclude you from local cyclists who may spend more time answering your questions because they feel a close connection with you. "basic psychology"