We've received the solar tax credit but even though we own a pair of EVs, they were purchased used and ineligible for the tax credit.
As you've noted, there's no roll-over for the EV credit. Be sure to place that credit in the correct place on your tax form.
My source for this part of the answer is the company that sold us the solar panels, which makes it only slightly suspect.
Solar credits can be applied until used up, unless repealed. You will determine how much credit to apply when you complete the form. If you do not apply the full amount to which you are entitled, the remainder will be available to enter on the following year.
I'm not a tax advisor and I don't play one on television, nor did I stay at a Holiday Inn Express. To be certain of this sales-backed information, one would want to consult a qualified tax advisor, but the odds are good that it's to your benefit.
Regarding the EV portion, a quick consultation with The Google presents this information direct from the IRS:
Use this form to claim the credit for certain plug-in electric
vehicles. Claim the credit for certain alternative motor vehicles on
Form 8910. Use a separate column for each vehicle. If you need more
columns, use additional Forms 8936 and include the totals on lines 12
The link to the form is located via the same search, form link here in PDF.
"Use a separate column for each vehicle" would lead one to believe that your multiple vehicles are covered. I believe that if the manufacturer has sold more than permitted to be covered by the tax credit, you will not be eligible, but have not pursued that line of research.