Really a deeper conversation is needed to dial everything in and I encourage OP to consult his CPA. 

In California, the LL must take reasonable steps to limit the damages of the tenant that broke the lease (i.e. they must be trying to minimize the vacancy time but are not required to lower their tenant standards).This is what is the law, but would a LL want a tenant that has to deal with Lynch Mob neighbors to be encouraged to continue living there? 

I'm just getting started in this STR world and I took a look at Guesty; which I really like but you need to own 4 properties to use their service and I currently have 1 property.What are some good alternatives to Guesty that have an updated platform?

It will be mixed use (we'll use it oct-dec). the onsite realtor is encouraging us to purchase a first-floor unit.

Could you have a roofer build a good platform for it to sit on, on the roof?

It encourages the tenant to leave when they are supposed to and allows you to sue for much higher rent if you need to evict after the lease is up. 

Even the platforms that are for landlords with a larger portfolio are great, but if you only have a few units -- from a pricing standpoint -- it may not make a whole lot of sense to go that route. 

Since you have reached a point where you've scaled up your family's REI portfolio a bit, it could make a lot of sense to go the PM route; or, you could continue to manage it yourself with a bit more guidance by using a proven platform to help you with the different steps of the process (ie. listing, tenant screening, digital lease creation, rent collection, maintenance tracking, etc).

Hi everyone. Has anyone ever used rent to retirement company to invest as a newbie or seasoned investor? Any advice is appreciated

Thanks, all, for your encouragement.