Yeah, the subjunctive would be a good solution for the first problem. Note, however, that you should use hic instead of huc, as huc expresses place towards "to here", whereas hic is more "in here".
There are several ways to express negative imperatives, but "non+imp" isn't one of them as far as I remember. The most common is to use noli/nolite+inf (the verb nolo literally means "I do not want", and is kin to volo et malo), "Noli dare gladium".
Alternatively you could use other expressions, such as ne+conjunctive perfect, "Ne dediris" or cave+subjunctive present (from caveo, beware), "Cave des". Those are the alternative ones I remember. The most common is definitely Noli+inf, though, and is the one you'll find most often.
I hope I was of help.