also for the MP map i believe there is a way using the triggers in which you could make it so that it doesnt depend on the houses (AKA maybe try the event of "when found by player" or whatever it is as im too lazy to open my FS up at the moment. as that SHOULD work and if you place it so that some of those buildings are in the starting point vicinity then youll get those buildings almost immediately. i think) and to make sure each side has to play as either GDI or Nod depending on their start position you could make it so something destroys the players starting MCV such as an ion cannon strike right at the beggining or something of that sort.
i use to have a Yuri's Revenge map by someone that was exactly like that almost. as in your starting MCV got destroyed almost instantly by prism towers then the prism towers sold and you got a base. if i can find that map again maybe i can tell you how it was done there and you could test it on your map. although i doubt ill be able to find it again.
also personally i like ion storms they make you think just a little bit more than normal as you have to constantly repair your base or else something will get destroyed. which makes the gameplay a little harder. but i dont think that one every 10 minutes that lasts for 5 minutes is a good idea. i think maybe a 2-3 minute one every 10 minutes might be better. or you could make it more advance and make it so the ion storm only happens say 3 times on the map and spread them out. which is easily done using local variables if you understand them that is. they really arent hard to learn
so theres my input for this. not much really just some ideas and stuff. hope to see the maps eventually