Disclaimer: IRL, I'm an extremely vengeful person. My boss would not want to do this to me, I would make it my personal mission to make their life as hellish as I could possibly think to do if I was in your shoes. That said, here is what I believe to be a reasonable middle ground between what I would actually do and what I think you should do.
The bottom line for all of the following is that they are recruiting you, not the other way around. You did not apply to this position, and you have no vested interest in getting it; as you said, you're moving in a few months so you don't care. That being the case, you are in a position of power here; you can always say "no" and then let your former boss take the ramifications of whatever that means for him; whatever those ramifications are are neither your business nor your concern, and if your boss doesn't want those ramifications to happen to him, then he'll have to do what you say.
Regarding pay: $25/hr is really really low for a software engineer. That works out to about $200/day (8 hrs/day), or about $1000/wk, or about $52k/yr (rough napkin math). That's really really bad pay unless you live in the middle of nowhere and are happy with that. What I would do is I would look at the market rate for a software engineer in your locale and ask for that as your salary. In my locale, being Toronto, Canada, the going rate is around $75k (Canadian dollars) for a junior developer. Given that your boss is trying to re-hire you, you are probably significantly above this level. Even if your skill level is not significantly above this level, you should charge them an additional fee on top of the "reasonable" salary level for your locale, because you have the power in the negotiation. If this was my locale, I would ask for $100k/yr (roughly $50/hr). A 100% raise sounds like a lot, but realistically speaking, you're being paid 66% of market rate (relative to my locale, I don't know about yours); against market rate you're only asking a 30% raise, and that's assuming you're a junior new grad (which I presume you're not). It sounds like a lot, but it's completely reasonable imo.
Regarding benefits: Have it written into your contract that you can come to work anytime before 10am. You don't want to have the same situation as before. Aim for 9:30, but if stuff happens, then you'll arrive at 10 without a problem. Also ensure that you get all employee benefits from day 1, whatever that means for your locale. For example, some companies don't give their employees access to company health insurance until 3 months into the job ("probation period"); make sure this isn't you. You worked for them previously, and they don't get to reneg on their employee benefits for 3 months (or whatever the standard period is for this stuff in your locale) by "firing and then re-hiring" you. Speaking of a probation period, ensure there isn't one. If you don't live in an at-will employment district (US terminology, basically means the employer can fire you at any time for any reason), you should have it written into your contract that the standard termination policy applies from day one. Once again, they don't get to game you.
I would consider pushing for a non-refundable signing bonus. They have already proven to be untrustworthy by firing you once; you want them to have an incentive to not jerk you around again by hiring you and then immediately firing you again. One way you can do this is by leveraging a large signing bonus against your salary ask. For example, if your salary ask is $100k/yr (see above), you can do something like, ask for a $95k/yr salary and a non-refundable signing bonus of $10k paid upon signing of the contract. In this case, this provides an incentive for them to keep you for at least 2 years; after 2 years you have made "an average" of $100k/yr, and then every subsequent year you average less than they otherwise would have paid you (assuming you don't get a raise, which is hopefully not the case, but worst-case this is what it would mean). To take the opposite extreme, if you walk into work and immediately they tell you to go home and not come back, you've spent about 30 minutes and gotten paid $10k, which is $20,000/hr! That's some pretty good salary!
Regarding moving: Don't say anything. Just do it. However, if you are moving, you don't have a job in that locale, meaning for all intents and purposes, you are still "unemployed". I don't know the details (I am not HR), but I don't think the usual strategy of being more attractive due to current employment applies to your situation.