In general, any graft is weaker than a tree that hasn't been cut and re-appended, because the intervention disrupts the original vasculature, resulting in a suboptimal path of nutrients from the roots. Graft failure can become apparent years later and be precipitated by drought (exactly what you were trying to avoid!). The best (albeit time-intensive) way to combine desired characteristics of different species (such as drought/heat tolerance, growth rate, color, etc) is hybridizing them and screening the progeny. It's amazing how easily firs from different continents can hybridize: http://www.agriculturejournals.cz/publicFiles/05120.pdf A good article describing the natural environments of Mediterranean firs (and hence the conditions they'll likely be able to withstand) is the following: http://utenvironment.org/upload_cec_files/abies_drought_comparison.pdf There is great variation within a single species depending on the elevation where the seed was collected, as can be seen in Figure 8. Abies concolor apache is simply the species, collected from Apache National Forest in Arizona. It is not, however, the most drought tolerant provenance. Seeds from either Cibola National Forest or Lincoln National Forest in New Mexico should yield white firs with better drought/heat resistance. You can buy the seeds from Better Forest Tree Seeds: http://www.betterforesttreeseeds.com/dial_truefir.htm The only commercially available seeds of Abies lasiocarpa arizonica are from Apache National Forest. You can buy them from: https://sheffields.com/seed_genus_species_lot/Abies/lasiocarpa/100400///arizonica//

Always tough to tell on color mutations if they are stable or some sort of nutrient or other problem. Monitor it over the spring/winter/fall and see how it evolves. If it buds out normally in the spring that's a good sign, then you can see if it's a winter/cold weather color changer or all season. By next fall/winter you should have a good idea if it's worth sending to grafters or learning to graft yourself

Ditto the "like well-drained soil" part. Ive got 3 little concolors (2 footers, basic abies concolor) that have been in the ground about 3 years. Started out with 6 and the three I lost were bc I did not build my mounds big enough, My soil is very wet as my water table is currently at 1 foot and this is in central ohio (sometimes I dig up leeches when I plant trees). So make sure they have good drainage.

Cupressus macrocarpa is the famous coastal conifer here, and there is a cultivar 'Coneybearii Aurea' that is golden, weeping and threadneedle. Gets pretty big, though! Some others but I can't think of other weepers off the top of my head.