This would be a bad idea.
Chicken should be cooked 1-2 days after refrigeration according to the USDA and other food safety agencies, and will tend to get noticeably slimy and pungent after 3-4 days in my experience. 5 days is really pushing it.
I understand the rationale for the question - lemon juice can kill the surface bacteria - but that's just the problem, salmonella bacteria don't only exist on the surface of chicken, they're crawling around the interior as well.
In order for this to be considered safe, you would need to be absolutely sure of all the following:
The entire marinade had a pH of significantly less than 4. Lemon juice is considered to have a base pH of 2-3, but that is fresh lemon juice and undiluted. Unless you actually used a pH tester, you cannot be 100% positive of this.
The marinade completely penetrated every part of the chicken that may have been contaminated. This is literally impossible for you to measure.
The chicken itself was relatively fresh before it went into the marinade - unless you got it farm-fresh, you don't know this for a fact, so even if the marinade completely penetrated the chicken, the interior bacteria may have already left behind some nasty protein toxins (which the marinade can't kill because they aren't alive).
If you had said 3 days, maybe 4, I would say, practically, that you'd probably be OK. But any more than that and you're playing with fire.
As the old chef's saying goes: When in doubt, throw it out.
If you are intent on eating it anyway then please, at least be responsible and don't serve it to any guests.
I once left a whole New York strip in the walk in cooler for two weeks and it was great. Chances are that the salt and acid in the marinade preserved the pork well enough it would still be safe to eat after six days. I would check for slime and foul odor. There are several other factors involved such as how it was handled before put in the refrigerator. For example, a piece of pork that was at room temp for one hour with a semi sterile knife trimming it might not last three days. I always go with whether it has an off odor or not. I find that meat which has aged a little in the fridge will have a more robust defined flavor. If you run your finger across it and feel any type of slime just get rid of it.
Best Answer
As far as safety goes, you're fine, assuming the meat didn't stay unfrozen for too long before you refroze it.
As far as the efficacy of the marinading process, I'd think that the freezing/freezer burning process would go a long way toward preventing the marinade from imparting a lot of flavour and/or tenderness. Still, 3 days frozen is nothing. Shouldn't hurt anything.