"Proceed with caution" is the common theme about Key Lime.

I heard they just got thier 121 cert...

<just what I heard>

I wonder if the PFT FOs were used to help supplement the PIC's salary and the company had to cut pay since PFT FOs are in short supply?

Stupid question but how does it work there, do they even need FO for all aircrafts? For example I have seen Bemidji Aviation fly PA-31 single pilot

They're 135 freight, so no they don't require it. They were doing some pax charter awhile back, and maybe they still are. For that you need an exemption from the FSDO (requires an autopilot, headset with boom mike, etc.) to operate single pilot. Pretty much 99.9% of 135 pax operators have this exemption, so I'm sure they do if it applies to them. I used to fly a PA-31-350 single pilot for a 135 pax charter operation, it was not a big deal as far as the checkride and FAA signoff for the exemption.

Even with the single pilot exemption, many 135 pax operators choose to operate with a 2 pilot crew for a variety of reasons (pax comfort, insurance, safety, etc.). Some real cheap scumbag operators charge the right seater money to sit there, and actually use it as a money maker for the company. That seems to be more common with the freight operators than the pax charter guys.

If it's pax charter, the right seater can log SIC time ONLY if they've had a 135 checkride and oral from a designated check airman (FAA, chief pilot, etc.). It gets a little trickier for 135 freight, but I know Airnet had a legitimate, FAA approved way for right seaters to log SIC time.

As far as working for Key Lime, doing a thorough search on them would be smart.

Maybe so, but in this current job market I would guess that there are SIC's lining up at the door to pay and play.

I just got a call for an interview for Metro PIC position. I see they are in CAST, but is it feasible to commute at all? Do they force you to fly the 5th day? Is there anyone on here that currently works for them, if so what is your opinion the place? Heard a lot of second hand info but nothing from someone that is there now.

Thats because they jump ship as soon as able... Commuting in CASS is easy if you have 3-4days off. I'm not sure about Key Lime but at Ameriflight it was difficult because you flew 5 days a week which left you with 2 days to JS.
Let us know how you like it.

Is Ameriflight in CASS or do they just have a jump seat agreement with South West ONLY...

When I was there we were in CASS. But being in CASS does not promise you a seat. Many airlines also require a reciprocal agreement in addition to CASS. We had Southwest. Not sure if they added anyone else lately.