The EU Army thing is a bit weird to bring up. Even assuming that the EU does get around to introducing it, which is doubtful (and, ironically, more likely with the UK outside than in) conscientious objection is still a thing, so it's not like anyone can be forced to join.
The only law preventing Johnson from having an election is the Fixed-Term Parliament Act, which was passed in 2011 after a long -- and, presumably, not entirely rigorous -- consultation. The speed at which the No Deal legislation is introduced is, in the meantime, clearly dictated by circumstances. Regardless of the rights of wrongs of the law, there would clearly be no point in taking months or even weeks to debate a law that needs to be ready by this Wednesday if it's to have any purpose at all.
And, besides, it's also worth noting that, even if we do agree a deal with the EU -- or, for that matter, leave with No Deal -- then the lack of time before departure is going to necessitate even more laws being passed far more quickly than usual.