It is only legal if you have permission from the publisher of the programs. This may be stated somewhere in the license, but if it isn't, you'll need to contact the publisher yourself and ask for permission. As a rule, if the license does NOT explicitly state that you may copy and redistribute the software, then you are NOT allowed to.
You should see a lawyer if you need any further information as SP is not a qualified legal advisor
some freewares specifically state no redistribution without consent nor selling the freeware for a profit without consent. i would read the terms of the freeware you want to sell and also content the publisher of it.
You will have to look at this one software program at a time... they all can have different license agreements and I can guarantee you that some of them will probably have restrictions on distribution, especially if you are charging a fee.