Interspecific pollination is kinda hit or miss...The Ipomoea spp. may not come true from seed or they may...lots of biological and structural issues come into play...However, your multifada var. are the same species and you'll probably end up with something new...same with the quamoclit respectively...All the other vines are from completely different genus and most of them are from entirely different familys so you're probably not gonna have any problems with them...If you do get some weird new morning glory varities from the collected seed, you might have some really gorgous plants that no one has seen before...
Peace,
Nathan

I REALLY appreciate this info....I'll get a hang of this someday...

Hello,
Interspecific hybrids are extremely rare in Convolvulaceae,as there are less than 25 grand total in Ipomoea and most of those being the result of hand pollination using very advanced techniques...natural interspecific hybrids are less than 5 and all in the series batatas...
Plants that are truely the same species may cross fertilize.
The Ipomoea quamoclit may cross and this may produce a pink color...the 'Hearts and Honey' vine I last saw advertised as an Ipomoea coccinea,but any of the Ipomoea x multifida,actually now using the updated binomial of Ipomoea sloteri,are tetraploids and will not cross with any other non-polyploid species.
Hope that helps...

Here is a link that might be useful: PlantFiles database at DavesGarden

You mentioned you wanted to plant the trumpet vine. I WOULD NOT recommend you plant this vine as it sends out suckers up to 20-30 feet away. You will regret planting it as it's such HIGH maintenance.