Hopefully I can answer a few of your questions...

Video #1 - That is a nice female boa. But she needs to see a qualified and experienced herp vet. I know you said there wasn't one in your area, but you need to find someone and take her there. That lump is most definitely not normal. If it's a tumor, she'll need care. I can tell you with a fair bit of certainty that it is not a rat bite. If it were, there would be visible scarring on the scales. This looks to be something going on under the skin - which makes it more worrisome to me. We are not vets here and even if we were, we could not make a diagnosis without actually putting our hands on the snake and examining her. Keep us posted on this - we'd all like to know what's up.

Video #2 - First off, that is a normal Columbian BCI. He is a nice snake and has a nice slightly reduced pattern, but he is what's referred to as a common central american or columbian boa. He is most likely that small because he probably didn't eat much at all while he was missing. Snakes don't need to subsist on much in order to survive. He probably never managed to come across more than a tiny mouse or two each month which means he just wouldn't grow fast at all. He'll catch up. You female is bigger because she's had larger and more consistent meals while growing, she's a female and they get bigger anyhow, and she is also a BCC or has BCC blood which means she'd be bigger anyway.

DO NOT POWERFEED your male!!! Boas do not do well with this and should never be powerfed. He WILL catch up - please just be patient.

Also, take off the gloves. I know he's a wild child, but I'd freak out too if those big scarey black things came reaching in and grabbed me. Young boas can often be pissy and he's not been handled for nearly 2 years. Give him a break - he's not gonna tame down over night. Be patient, slow, and gentle. Don't grab and yank him out and twist him around and manhandle him. I'm not being critical here - you needed to bring him out to show on the vid and that's fine, just slow down from now on and consider things from his point of view. Their bite doesn't hurt and he's too little to do much damage. Try to handle him for about 30min each day and slide your (ungloved) hand underneath him and gently scoop him up rather than grab and lift. If he does bite, don't jerk (easier said than done, lol) and just let him figure out that the bite doesn't get him anywhere. He's biteing from fear, not aggression.

Hope this helps you! Keep us posted on how things are going....